Case Studies

1. Microwave and THz Material Characterisation

Led by Dr Stephen M. Hanham (Department of Materials)
Professor Norbert Klein (Department of Materials)
Andrew Gregory, National Physical Laboratory (NPL)

The development of the terahertz region of the electromagnetic spectrum is heavily dependent on new materials that will underpin future terahertz devices and systems. Our Centre, in collaboration with NPL, has developed the capability to characterise the properties of materials over the frequency range 1 GHz to 3 THz. This large frequency range is covered using a number of different instruments and techniques that offer different levels of sensitivity and traceability.

One instrument that has been developed over the last few years is a near-field microwave microscope that allows the dielectric and conductive properties of materials to be imaged with a spatial resolution of several microns. This instrument is particularly useful for imaging thin films where the quality and consistency of films (such as graphene) can be assessed. Other instruments include the quasi-optical setups that exploit the VNA’s and the terahertz time-domain spectrometer’s ability to measure up to 500 GHz and 3 THz, respectively, to characterise materials. 

microwave

(a) A THz quasi-optical system designed for the characterisation of materials from 67 GHz to 500 GHz. (b) System diagram of a near-field microwave microscope designed for material measurements with micron-level spatial resolutions. (c) Simulated electric field of the near-field probe (d) Time and frequency domain signals generated by our THz time-domain spectrometer used for measurements up to 3 THz.

Journal Papers

  1. A. P. Gregory, J. F. Blackburn, K. Lees, R. N. Clarke, T. E. Hodgetts, S. M. Hanham, and N. Klein, “Measurement of the permittivity and loss of high-loss materials using a Near-Field Scanning Microwave Microscope,” Ultramicroscopy, vol. 161, pp. 137–145, Feb. 2016.
  2. S. Goniszewski, M. Adabi, O. Shaforost, S. M. Hanham, L. Hao and N.Klein, "Correlation of p-doping in CVD Graphene with Substrate Surface Charges," Sci. Reports., Sci. Rep., vol. 6, p. 22858, Jan. 2016.
  3. O. Shaforost, K. Wang, S. Goniszewski, M. Adabi, Z. Guo, S. Hanham, J. Gallop, L. Hao, and N. Klein, “Contact-free sheet resistance determination of large area graphene layers by an open dielectric loaded microwave cavity,” J. Appl. Phys., vol. 117, no. 2, p. 024541, Jan. 2015
  4. A. Gregory, L. Hao, N. Klein, J. Gallop, C. Mattevi, O. Shaforost, K. Lees, and B. Clarke, “Spatially resolved electrical characterisation of graphene layers by an evanescent field microwave microscope,” Physica E: Low-dimensional Systems and Nanostructures, vol. 56, pp. 431-434, Feb. 2014
  5. L. Hao, J. Gallop, S. Goniszewski, O. Shaforost, N. Klein, R. Yakimova, “Non-contact method for measurement of the microwave conductivity of graphene,” Appl. Phys. Lett., vol. 103, no. 12, p. 123103, Sep. 2013
  6. L. Hao, C. Mattevi, J. Gallop, S. Goniszewski, Y. Xiao, L. Cohen, N. Klein,  “Microwave surface impedance measurements on reduced graphene oxide,” Nanotechnology, vol. 23, no. 28, p. 285706, Jul. 2012

 Conference Papers

  1. 1. S. M. Hanham, A. Gregory and N. Klein, "A Tapered Parallel-plate Waveguide Probe for Near-field Terahertz and Microwave Imaging and Metrology," Photonics 2016, Leeds, U.K., Sept. 2016. 
  2. N. Klein, S. M. Hanham, T. H. Basey-Fisher, C. Watts, O. Shaforost, W. J. Otter and S. Lucyszyn, “Micro- and millimetre wave measurements of nanolitre biological liquids by dielectric resonators,” IEEE International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-Bio2014), London, pp. 90-92, Dec. 2014 (Invited)
  3. N. Klein, O. Shaforost, K. Wang, G. Zhexi, M. Adabi, S. M. Hanham, P. K. Petrov, W. J. Otter, M. Navarro-Cia, S. Lucyszyn and L. Hao, “Microwave-to-terahertz investigation of CVD graphene: towards sensor and communication applications”, 39th International Conference on Micro and Nano Engineering (MNE 2013), London, p. 223, Sep. 2013
  4. O. Shaforost, K. Wang, M. Adabi, Zh. Guo, L. Hao, J. Gallop, and N. Klein “Microwave characterization of large area graphene using a TE01δ dielectric resonator” MSMW’13, Kharkov, Ukraine, pp 427-429, Jun. 2013
  5. S. M. Hanham, A. Gregory, S. A. Maier, N. Klein, “A dielectric probe for near-field millimeter-wave imaging,” 37th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz 2012), Wollongong , Australia, Sep. 2012

 

2. Graphene

Led by Professor Norbert Klein (Department of Materials)
Dr Olena Shaforost, Dr Stephen M. Hanham, Mohammad Adabi, Stefan Goniszevski (Department of Materials)
Dr Antonio Lombardo, Cambridge Graphene Centre
Professor Yang Hao, School of Electrical Engineering and Computer Science,  Queen Mary University London

Graphene is one of the most promising new materials for the realization of low cost THz devices, which include critical components like mixers, attenuators, modulators, and detectors. As a technological basis, we have established a 4” wafer scalable process for graphene deposition, by chemical vapour deposition (CVD) as well as etching processes, to fabricate integrated graphene planar circuits on THz substrates like quartz and high resistivity silicon. Our previous work has focused on the manufacturing of high quality graphene, including optimization of the CVD and transfer processes, as well as the preparation of free-standing graphene microstructures on silicon substrates. Moreover, we have studied various microwave-to-terahertz characterization techniques for qualification of graphene for THz applications. Our future work will be directed to the practical realization of graphene THz detectors, harmonic generators and fast modulators, aiming towards low-cost THz communication and sensing systems

graphene
Free standing graphene drum and new 4” CVD kit within the Department of Materials

Journal Papers

  1. S. Goniszewski, M. Adabi, O. Shaforost, S. M. Hanham, L. Hao and N.Klein, "Correlation of p-doping in CVD Graphene with Substrate Surface Charges," Sci. Reports., Sci. Rep., vol. 6, p. 22858, Jan. 2016.
  2. O. Shaforost, K. Wang, S. Goniszewski, M. Adabi, Z. Guo, S. Hanham, J. Gallop, L. Hao, and N. Klein, “Contact-free sheet resistance determination of large area graphene layers by an open dielectric loaded microwave cavity,” J. Appl. Phys., vol. 117, no. 2, p. 024501, Jan. 2015
  3. A. Gregory, L. Hao, N. Klein, J. Gallop, C. Mattevi, O. Shaforost, K. Lees, and B. Clarke, “Spatially resolved electrical characterisation of graphene layers by an evanescent field microwave microscope,” Physica E: Low-dimensional Systems and Nanostructures, vol. 56, pp. 431-434, Feb. 2014
  4. L. Hao, J. Gallop, S. Goniszewski, O. Shaforost, N. Klein, R. Yakimova, “Non-contact method for measurement of the microwave conductivity of graphene,” Appl. Phys. Lett., vol. 103, no. 12, p. 123103, Sep. 2013
  5. L. Hao, C. Mattevi, J. Gallop, S. Goniszewski, Y. Xiao, L. Cohen, N. Klein,  “Microwave surface impedance measurements on reduced graphene oxide,” Nanotechnology, vol. 23, no. 28, p. 285706, Jul. 2012

 Conference Papers

  1. S. M. Hanham, M. Adabi, P. A. Huidobro and N. Klein, "Terahertz Optical Hall Effect Analysis of Graphene," Int. Conf. on Semiconductor Mid-IR and THz Materials and Optics (SMMO2016), 2016.
  2. S. Goniszewski, O. Shaforost, J. Gallop, L. Hao, D. Cox, and N. Klein, “Frequency readout of nanomechanical graphene drums via a microwave resonator coupling method”, Conference Proceedings of the 44th European Microwave Conference (EuMC 2014), Rome, Italy, Oct. 2014
  3. S. Goniszewski, O. Shaforost, J. Gallop, L. Hao, D. Cox, N. Klein “Realisation of suspended CVD graphene drums based on perforated SiN membranes”, Conference Proceedings 11th International Workshop on Nanomechanical Sensing (NMC 2014), Madrid, Spain, Apr. 2014
  4. N. Klein, O. Shaforost, K. Wang, G. Zhexi, M. Adabi, S. M. Hanham, P. K. Petrov, W. J. Otter, M. Navarro-Cia, S. Lucyszyn and L. Hao, “Microwave-to-terahertz investigation of CVD graphene: towards sensor and communication applications”, 39th International Conference on Micro and Nano Engineering (MNE 2013), London, UK, p. 223, Sep. 2013
  5. O. Shaforost, K. Wang, M. Adabi, Zh. Guo, L. Hao, J. Gallop, and N. Klein “Microwave characterization of large area graphene using a TE01δ dielectric resonator”, MSMW’13, Kharkov, Ukraine, pp. 427-429, Jun. 2013

 

3. THz Waveguides

Led by Dr Miguel Navarro-Cía (Department of EEE)
Dr Oleg Mitrofanov, Department of EEE, University College London
Professor James A Harrington, School of Engineering, Rutgers University, USA

The strong absorption of most media in the THz range and the strong atmospheric attenuation (especially above 1 THz) impede efficient transmission of THz waves. A way to circumvent the problem is to use propagation via hollow waveguide modes with minimal field distribution in the walls of the waveguide.

The dielectric-lined hollow metallic waveguide holds promise in this regard, because it supports a low-loss and low-dispersive hybrid HE11 mode within a wide band. The fabrication of this waveguide for THz frequencies is not trivial, especially when they are made bendable, and the fabricated samples need to be tested.

We use near-field time-domain microscopy for measuring the samples to mitigate the characterization problems related to mode interference, pulse dispersion, large variation of the coupling coefficient and loss with frequency. 

waveguides
(Left) Waveform detected on the Teflon-lined hollow metallic waveguide axis. (Right) Power spectral density of the measured waveform shown on the left-hand side. The numerically-computed group delay for the TM11-HE11 (dotted violet) and the TM12 modes (dotted green) are superimposed.

Journal Papers

  1. M. Navarro-Cía, J.E. Melzer, J.A. Harrington, and O. Mitrofanov, “Silver-coated Teflon tubes for pulse waveguiding at 1-2 THz,” J. of Infrared, Milli. and Terahertz Waves, vol. 36, no. 6, pp. 542-555, Jun. 2015
  2. M. Navarro-Cía, M.S. Vitiello, C.M. Bledt, J.E. Melzer, J.A. Harrington, and O. Mitrofanov, “Terahertz wave transmission in flexible polystyrene-lined hollow metallic waveguides for the 2.5-5 THz band,” Optics Express, vol. 21, no. 20, pp. 23748-23755, Sep. 2013
  3. M. Navarro-Cía, R. Mueckstein, and O. Mitrofanov, “Comment on ‘The transition from a TEM-like mode to a plasmonic mode in parallel-plate waveguides’ [Appl. Phys. Lett. 98, 231113 (2011)],” Appl. Phys. Lett., vol. 102, no. 24, pp. 246103-1-2, Jun. 2013
  4. R. Mueckstein, M. Navarro-Cía, and O. Mitrofanov, “Mode interference and radiation leakage in a tapered parallel plate waveguide for terahertz waves,” Appl. Phys. Lett., vol. 102, no. 14, pp. 141103-1-4, Apr. 2013
  5. M. Navarro-Cía, C.M. Bledt, M.S. Vitiello, H.E. Beere, D.A. Ritchie, J.A. Harrington, and O. Mitrofanov, “Modes in AgI-lined hollow metallic waveguides mapped by terahertz near-field time-domain microscopy,” J. Optical Soc. America B, vol. 30, no. 1, pp. 127-135,  Jan. 2013

 Conference Papers

  1. M. Navarro-Cía, J.E. Melzer, J.A. Harrington, and O. Mitrofanov, “Effective single HE11 mode propagation in silver-coated Teflon tubes for THz applications,” IEEE AP-S Int. Symp. on Antennas and Propag. 2015 and USNC/URSI National Radio Science Meeting 2015 (2015 IEEE AP-S/URSI), Vancouver, Canada, Jul. 2015
  2. M. Navarro-Cía, J. E. Melzer, J. A. Harrington, and O. Mitrofanov, “Low-loss THz pulse transmission in commercially available Teflon tubes coated with silver,” 39th Int. Conf. on Infrared, Millimeter, and Terahertz Waves 2014 (IRMMW-THz 2014), Tucson, U.S.A., Sept. 2014 
  3. J. E. Melzer, M. Navarro-Cía, O. Mitrofanov, and J.A. Harrington, “Silver-coated Teflon Hollow Waveguides for the Delivery of Terahertz Radiation,” SPIE Photonics West, San Francisco, U.S.A., Feb. 2014
  4. R. Mueckstein, M. Navarro-Cía, and O. Mitrofanov, “Understanding the Dispersion of THz Pulses in Tapered Parallel Plate Waveguides: Role of Multimode Propagation and Radiation Leakage,” 38th International Conference on Infrared, Millimeter, and Terahertz Waves 2013, IRMMW-THz 2013, Mainz, Germany, Sep. 2013
  5. M. Navarro-Cía, C.M. Bledt, J.E. Melzer, M.S. Vitiello, H.E. Beere, D. A. Ritchie, J.A. Harrington, and O. Mitrofanov, “Dispersion, attenuation and radiation on overmoded ultra-thin-AgI-coated metallic waveguides,” 38th International Conference on Infrared, Millimeter, and Terahertz Waves 2013, IRMMW-THz 2013, Mainz, Germany, Sep. 2013
  6. M. Navarro-Cía, C.M. Bledt, M.S. Vitiello, H.E. Beere, D. A. Ritchie, J.A. Harrington, and Oleg Mitrofanov, “Impact of thin AgI coatings on modes in cylindrical metallic waveguides for THz applications,” CLEO: 2013 Conference, San Jose, U.S.A., Jun. 2013
  7. R. Mueckstein, M. Navarro-Cía, and O. Mitrofanov, “Origins of dispersive terahertz pulse propagation in tapered parallel plate waveguides,” CLEO: 2013 Conference, San Jose, California, U.S.A., Jun 2013
  8. M. Navarro-Cía, C.M. Bledt, M.S. Vitiello, H.E. Beere, D. A. Ritchie, J.A. Harrington, and Oleg Mitrofanov, “Unveiling the mode structure of terahertz oversized electrically-thin-AgI-lined cylindrical waveguides via near-field time-domain microscopy,” 7th European Conference on Antennas and Propagation 2013, EuCAP2013, Gothenburg, Sweden, Apr. 2013
  9. M. Navarro-Cía, C.M. Bledt, M.S. Vitiello, H.E. Beere, D. A. Ritchie, J.A. Harrington, and Oleg Mitrofanov, “Interference of waveguide modes analyzed by THz near-field microscopy,” 5th International Workshop on Optical Terahertz Science and Technology 2013, OTST 2013, Kyoto, Japan, Apr. 2013

 

4. THz Plasmonics

Led by Professor Stefan Maier (Department of Physics)
Dr Binghao Ng, Dr Paloma Arroyo Huidobro (Department of Physics)
Dr Stephen M. Hanham (Department of Materials)
Dr Miguel Navarro-Cía (Department of EEE)

Plasmonics is a well-established field in the visible region of the electromagnetic spectrum, where surface plasmon modes on the surface of noble metals are often used for sensing. We have shown that by adopting semiconductor materials or engineering the texture of metal surfaces, plasmonic or plasmonic-like waves can be supported on a surface at terahertz frequencies, with similar properties to their visible wavelength counterparts.

The enhancement and confinement of the electromagnetic field associated with surface plasmon wave make them ideally suited for sensing applications. We have demonstrated how these waves can be used for performing spectroscopic sensing of extremely small quantities of solids and liquids.  

plasmonic

(a) A corrugated metal surface is used to support a THz spoof plasmon, used for sensing. (b) A multi-annular metamaterial used to guide several strongly confined spoof plasmon modes. (c) Two InSb touching disks that support a localised surface plasmon resonance at terahertz frequencies.

Journal Papers

  1. B. Ng, S. M. Hanham, J. Wu, A. I. Fernandez-Dominguez, N. Klein, Y. F. Liew, M. B. H. Breese, M. Hong, S. A. Maier,  “Broadband Terahertz Sensing on Spoof Plasmon Surfaces,” ACS Photonics, vol. 1, pp. 1059-1067, Sep. 2014
  2. B. Ng, S. M. Hanham, J. Wu, A. I. Fernandez-Dominguez, N. Klein, Y. F. Liew, M. B. H. Breese, M. Hong, S. A. Maier,  “Spoof Plasmon Surfaces: A Novel Platform for THz Sensing, Adv. Opt. Mat., Vol. 1, no. 8, pp. 543-548. Jun. 2013
  3. S. M. Hanham, A. I. Fernández-Domínguez, J. H. Teng, N. A. S. Seng, N. Klein, J. B. Pendry and S. A. Maier, "Broadband terahertz plasmonic response of touching InSb disks," Adv. Mat., vol. 24, no. 35, OP226-OP230, 2012

 Conference Papers

  • I. Khromova, O. Mitrofanov, M. Navarro-Cía, I. Liberal, I.Brener, J. Reno, L. Melnikov, and A. Ponomarev, “Resonant terahertz absorption in carbon microfibres,” Metamaterials’2015, Oxford, U.K., (Submitted Sept. 2015)
  1. I. Khromova, O. Mitrofanov, M. Navarro-Cía, I. Liberal, I. Brener, J. Reno, L. Melnikov, and A. Ponomarev, “Plasmonic Resonances in Carbon Microfibres for Engineerable Terahertz Absorption,” 7th International Conference on Surface Plasmon Photonics, SPP7, Jerusalem, Israel, Jun. 2015
  2. S. M. Hanham, M. Navarro-Cía, B. Ng, H. Aouani, M. Rahmani, N. Klein and S. A. Maier, "Exploiting plasmonics for THz and infrared sensing," Proc. SPIE 9102, Balitmore, U.S., May 21, 2014 (Invited)
  3. M. Navarro-Cía, S.A. Maier, M. Beruete, F. Falcone, M. Sorolla, and, “Optimized dual-band planar THz waveguide,” 6th European Conference on Antennas and Propagation 2012, EuCAP2012, Prague, Czech Republic, Mar. 2012

 Book Chapters

  1. S. M. Hanham and S. A. Maier, "Terahertz plasmonic surfaces for sensing," in Active Plasmonics and Tuneable Plasmonic Metamaterials,  A. V. Zayats and S. A. Maier, Eds. John Wiley & Sons, 2013, ch. 8, pp. 243-256
  2. S. Preu, G.H. Döhler, S. Malzer, A. Stöhr, T. Göbel, E. R. Brown, M. Feiginov, R. Gonzalo, M. Beruete, and M. Navarro-Cía, Principles of THz Generation, “Semiconductor TeraHertz Technology: Devices and Systems at Room Temperature Operation,” ISBN: 978-1-118-92042-8, Wiley-IEEE Press

5. THz Plasmonic Oscillators

Led by Dr Oleksiy Sydoruk (Department of EEE)
Professor Richard R. A. Syms and Professor Laszlo Solymar (Department of EEE)
Dr Kaushal Choonee, National Physics Laboratory (NPL)
Dr Gregory C Dyer, Sandia National Laboratories, USA

A timely problem for terahertz technology is the need for more effective sources. While existing methods of generation are being actively refined, an intensive search for alternatives is underway. Relying on rigorous solutions of Maxwell’s equations, we have been theoretically studying terahertz amplification and generation in a two-dimensional semiconductor channel supporting drifting plasmons. We have shown that transfer of power is possible from a dc current to THz plasmons. In addition, we have developed a theoretical model of passive plasmonic resonators, comprising gated and non-gated electron channels. 

oscillators
A junction between gated and non-gated channels leads to partial plasmon reflection, which can be used to design resonators

Journal Papers

  1. O. Sydoruk, K. Choonee and G. C. Dyer, “Transmission and reflection of terahertz plasmons is two-dimensional plasmonic devices”, IEEE Trans. Terahertz Sci. Tech, vol. 5,no. 3, pp. 486-496, Mar. 2015
  2. O. Sydoruk “Amplification and generation of terahertz plasmons in gated two-dimensional channels: modal analysis”, J. Appl. Phys., vol. 115, p. 204507, May 2014
  3. O. Sydoruk, “Amplification of drifting semiconductor plasmons and effects of carrier collisions and diffusion”, J. Phys. D.: Appl. Phys., vol. 46, no. 34, p. 345101, Aug. 2013
  4. O. Sydoruk, “Drifting plasmons in open two-dimensional channels: modal analysis,” J. Phys. D. Appl. Phys., vol. 46, no. 13, p. 135103, Feb. 2013
  5. O. Sydoruk, R. R. A. Syms, and L. Solymar “Amplifying mirrors for terahertz plasmons” J. Appl. Phys.  vol. 112, no. 10, p. 104512, Nov. 2012
  6. O. Sydoruk, R. R. A. Syms, and L. Solymar, "Distributed gain in plasmonic reflectors and its use for terahertz generation," Opt. Express, vol. 20, no. 18, pp. 19618-19627, Aug. 2012

 Conference Paper

  1. O. Sydoruk “Is amplification of semiconductor plasmons possible despite carrier collisions and diffusion”, 38th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz 2013), Mainz, Germany, Sep. 2013

6. THz Metamaterials

Led by Dr Miguel Navarro-Cía (Department of EEE)
Dr Miguel Beruete, Antennas Group-TERALAB, Universidad Pública de Navarra, Spain
Professor Nader Engheta, University of Pennsylvania, USA
Dr Sergei A. Kuznetsov, Novosibirsk State University, Russian Federation
Professor Tahsin Akalin, Institute of Electronics, Microelectronics and Nanotechnology (IEMN), Lille University, France

A new class of quasi-optical components can be designed with metamaterials. These components are characterized by subwavelength features that tailor their overall electromagnetic response. The new design philosophy has made possible the implementation of free-space matched diffractive optical devices without expensive and cumbersome anti-reflective coatings. Our effort is focused on developing robust metallic lenses, frequency selective surfaces and low-profile highly-directive antennas for radar and space applications.

metamaterials
From left to right: 144 GHz epsilon-near-zero lens based on narrow rectangular waveguides operating near cut-off, THz quarter-wave plates based on the extraordinary transmission phenomenon and THz leaky-wave slit+grooves antenna

Journal Papers

  1. B. Orazbayev, M. Beruete, V. Pacheco-Peña, G. Crespo, J. Teniente, and M. Navarro-Cía, “Soret Fishnet metalens antenna,” to be published in Scientific Reports, 2015
  2. U. Beaskoetxea, V. Pacheco-Peña, B. Orazbayev, T. Akalin, S. Maci, M. Navarro-Cía, and M. Beruete, “77 GHz High Gain Bull’s Eye Antenna with Sinusoidal Profile,” IEEE Antennas and Wireless Propagation Letters, vol. 14, pp. 205-208, Feb. 2015
  3. S.A. Kuznetsov, M.A. Astafev, M. Beruete, and M. Navarro-Cía, “Planar Holographic Metasurfaces for Terahertz Focusing,” Scientific Reports, vol. 5,  no. 7738, pp. 1-8, Jan. 2015
  4. V. Torres, B. Orazbayev, V. Pacheco-Peña, J. Teniente, M. Beruete, M. Navarro-Cía, M. Sorolla Ayza, and N. Engheta, “Experimental demonstration of a millimetre-wave metallic lens based on the energy squeezing principle,” IEEE Trans. Antennas Propag., vol. 63, no. 1, pp. 231-239, Jan. 2015
  5. V. Pacheco-Peña, V. Torres, B. Orazbayev, M. Beruete, M. Navarro-Cía, M. Sorolla, and N. Engheta, “Mechanical 144 GHz beam steering with all-metallic epsilon-near-zero lens antenna,” Appl. Phys. Lett., vol. 105, no. 24, pp. 243503-1-5, Dec. 2014
  6. V. Pacheco-Peña, V. Torres, M. Beruete, M. Navarro-Cía, and N. Engheta, “e-near-zero (ENZ) graded index quasi-optical elements: steering and splitting millimeter waves,” J. Optics, vol. 16, no. 9, pp. 094009-1-7, Sep. 2014. Selected by the editors for the 'Highlights of 2014' collection; Fig. 4 was selected cover page of the special issue on mid-infrared and THz photonics (Invited)
  7. V. Torres, N. Sánchez, D. Etayo, R. Ortuño, M. Navarro-Cía, A. Martínez, and M. Beruete, “Compact Dual-Band Terahertz Quarter-Wave Plate Metasurface,” IEEE Photonics Technol. Lett., vol. 26, no. 16, pp. 1679-1682, Aug. 2014
  8. V. Torres, R. Ortuño, P. Rodríguez-Ulibarri, A. Griol, A. Martínez, M. Navarro-Cía, M. Beruete, and M. Sorolla, “Mid-infrared plasmonic inductors: Enhancing inductance with meandering lines,” Scientific Reports, vol. 4, no. 3592, pp. 1-5, Jan. 2014
  9. M. Beruete, U. Beaskoetxea, M. Zehar, A. Agrawal, S. Liu, K. Blary, A. Chahadih, X.-L. Han, M. Navarro-Cía, D. Etayo, A. Nahata, T. Akalin, and M. Sorolla Ayza, “Terahertz corrugated and bull's-eye antennas,” IEEE Trans. THz Sci. Technol., vol. 3, no. 6, pp. 740-747,  Nov. 2013 (Invited)
  10. M. Navarro-Cía, M. Natrella, F. Dominec, J.-C. Delagnes, P. Kužel, P. Mounaix, C. Graham, C.C. Renaud, A.J. Seeds, and O. Mitrofanov, “Terahertz imaging of sub-wavelength particles with Zenneck surface waves,” Applied Physics Letters, vol. 103, no. 22, pp. 221103-1-5, (2013)
  11. V. Torres, V. Pacheco-Peña, P. Rodríguez-Ulibarri, M. Navarro-Cía, M. Beruete, M. Sorolla, and N. Engheta, “Terahertz epsilon-near-zero graded-index lens,” Optics Express, vol. 21, no. 7, pp. 9156-9166, Apr. 2013
  12. M. Navarro-Cía, P. Rodríguez-Ulibarri, M. Beruete, “Hedgehog subwavelength hole arrays: control over the THz enhanced transmission,” New J. Phys., vol. 15, no. 1, pp. 013003-1-9,  Jan. 2013
  13. S. M. Hanham, A. I. Fernández-Domínguez, J. H. Teng, N. A. S. Seng, N. Klein, J. B. Pendry and S. A. Maier, “Broadband terahertz plasmonic response of touching InSb disks,” Adv. Mat., vol. 24, no. 35, OP226-OP230, Jul. 2012

 Book chapter

  1. S. Goniszewski, O. ShaforostPreu, G.H. Döhler, S. Malzer, A. Stöhr, T. Göbel, E. R. Brown, M. Feiginov, R. Gonzalo, M. Beruete, and M. Navarro-Cía, Principles of THz Generation, “Semiconductor TeraHertz Technology: Devices and Systems at Room Temperature Operation,” ISBN: 978-1-118-92042-8, Wiley-IEEE Press.

 Conference Papers

  • V. Torres, V. Pacheco-Peña, B. Orazbayev, J. Teniente, M. Beruete, M. Navarro-Cía, M. Sorolla, and N. Engheta, “Epsilon-near-zero lens for beamshaping of sub-terahertz waves,” 40th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Hong Kong, China, (Submitted Mar. 2015)
  1. V. Pacheco-Peña, M. Beruete, M. Navarro-Cía, I.V. Minin, and O. V. Minin, “High resolution terajets using 3D cuboids,” IEEE AP-S International Symposium on Antennas and Propagation 2015 and USNC/URSI National Radio Science Meeting 2015 (2015 IEEE AP-S/URSI), Vancouver, Canada, Jul. 2015
  2. U. Beaskoetxea, M. Beruete, F. Falcone, D. Etayo, M. Sorolla, M. Navarro-Cía, M. Zehar, K. Blary, A. Chahadih, X.-L. Han, and T. Akalin, “High gain leaky wave antenna operating at 0.566 THz,” IEEE AP-S International Symposium on Antennas and Propagation 2015 and USNC/URSI National Radio Science Meeting 2015 (2015 IEEE AP-S/URSI), Vancouver, Canada, Jul. 2015
  3. V. Torres, V. Pacheco-Peña, B. Orazbayev, J. Teniente, M. Beruete, M. Navarro-Cía, M. Sorolla, and N. Engheta, “144 GHz Epsilon-Near-Zero Lens Antenna,” IEEE AP-S International Symposium on Antennas and Propagation 2015 and USNC/URSI National Radio Science Meeting 2015 (2015 IEEE AP-S/URSI), Vancouver, Canada, Jul. 2015.
  4. S. Kuznetsov, M. Astafev, M. Beruete, and M. Navarro-Cía, “350 GHz Holographic Surface for Single- and Multi-focusing,” IEEE AP-S International Symposium on Antennas and Propagation 2015 and USNC/URSI National Radio Science Meeting 2015 (2015 IEEE AP-S/URSI), Vancouver, Canada, Jul. 2015
  5. S. A. Kuznetsov, M. A. Astafev, M. Beruete, and M. Navarro-Cía, "High-Performance Reflective Focusing of Terahertz Beams Using Holographic Metasurfaces," 36th Progress In Electromagnetics Research Symposium, Prague, Czech Republic, Jul. 2015
  6. V. Torres, B. Orazbayev, V. Pacheco-Peña, J. Teniente, M. Beruete, M. Navarro-Cía, M. Sorolla Ayza, and N. Engheta, “144 GHz Epsilon-Near-Zero Metamaterial Lens,” 9th European Microwave Conference on Antennas and Propagation 2015  (EuCAP2015), Lisbon, Portugal, Apr. 2015
  7. U. Beaskoetxea, V. Pacheco-Peña, B. Orazbayev, T. Akalin, S. Maci, M. Navarro-Cía, and M. Beruete, “High Gain Flat Sinusoidal Bull’s Eye Leaky Millimetre-Wave Antenna,” 9th European Conference on Antennas and Propagation 2015 (EuCAP2015), Lisbon, Portugal, Apr. 2015
  8. V. Torres, N. Sánchez, D. Etayo, M. Navarro-Cía, A. Martínez, and M. Beruete, “Compact Quarter-Wave Plate Metasurface at 1 and 2.2 THz,” 9th European Conference on Antennas and Propagation 2015 (EuCAP2015), Lisbon, Portugal, Apr. 2015
  9. U. Beaskoetxea, M. Beruete, F. Falcone, D. Etayo, M. Sorolla, M. Navarro-Cía, M. Zehar, K. Blary, A. Chahadih, and T. Akalin, “Low Profile THz Periodic Leaky-Wave Antenna,” 14th Mediterranean Microwaves Symposium 2014 (MMS’2014), Marrakech, Morocco, Dec. 2014
  10. B. Orazbayev, V. Torres, V. Pacheco-Peña, F. Falcone, M. Beruete, M. Sorolla, M. Navarro-Cía, and N. Engheta, “All-Metallic ε-Near-Zero (ENZ) Lens Based On Ultra-Narrow Hollow Rectangular Waveguides: Experimental Results,” 14th Mediterranean Microwaves Symposium 2014 (MMS’2014), Marrakech, Morocco, Dec. 2014
  11. U. Beaskoetxea, M. Beruete, M. Zehar, A. Agrawal, S. Liu, K. Blary, A. Chahadih, X.-L. Han, M. Navarro-Cía, D. Etayo, A. Nahata, T. Akalin, and M. Sorolla Ayza, “Flat THz Leaky Wave Antennas: Analysis and Experimental Results,” Metamaterials’2014, Copenhagen, Denmark, Aug. 2014
  12. V. Pacheco-Peña, V. Torres,  B. Orazbayev, M. Beruete, M. Navarro-Cía, and N. Engheta, “Focusing millimetre waves by means of a permittivity-near zero narrow-waveguide lens,” Metamaterials’2014, Copenhagen, Denmark, Aug. 2014  
  13. V. Torres, N. Sánchez, D. Etayo, R. Ortuño, M. Navarro-Cía, A. Martínez, and M. Beruete, “Compact Dual-Band Quarter-Wave Metaplate for the Terahertz Band,” Metamaterials’2014, Copenhagen, Denmark, Aug. 2014 
  14. U. Beaskoetxea, M. Navarro-Cía, F. Falcone, T. Akalin, M. Beruete, and M. Sorolla, “Extraordinary-Transmission-inspired Bull’s Eye Antenna for Automotive Radar,” IEEE AP-S Int. Symp. Antennas and Propag. 2014 and USNC/URSI National Radio Science Meeting 2014 (2014 IEEE AP-S/URSI), Memphis, Tennessee, U.S.A., Jul. 2014
  15. V. Torres, R. Ortuño, P. Rodríguez-Ulibarri, A. Griol, A. Martínez, M. Navarro-Cía, M. Beruete, and M. Sorolla, “Mid-infrared Plasmonic Inductors,” CLEO: 2014 Conference, San Jose, U.S.A., Jun. 2014 
  16. V. Torres, N. Sánchez, D. Etayo, R. Ortuño, A. Martínez, M. Navarro-Cía, and M. Beruete, “Extraordinary Transmission-inspired Dual-band THz Quarter-wave Plate,” CLEO: 2014 Conference, San Jose, U.S.A., Jun. 2014 
  17. U. Beaskoetxea, M. Beruete, M. Zehar, A. Agrawal, S. Liu, K. Blary, A. Chahadih, X.-L. Han, D. Etayo, M. Navarro-Cía, A. Nahata, T. Akalin, and M. Sorolla, “Flat THz Lacunher Antenna,” CLEO: 2014 Conference, San Jose, U.S.A., Jun. 2014 
  18. M. Navarro-Cía, M. Natrella, F. Dominec, J.-C. Delagnes, P. Kužel, P. Mounaix, C. Graham, C.C. Renaud, A.J. Seeds, and O. Mitrofanov, “Zenneck THz Surface Waves-assisted Imaging of Subwavelength Dielectric Particles,” CLEO: 2014 Conference, San Jose, U.S.A., Jun. 2014  
  19. W. Withayachumnankul, Y. Monnai, M. Navarro-Cía, and T. Akalin, “Terahertz periodic leaky-wave antennas with metamaterial scatterers,” 5th Int. Conf. on Metamaterials, Photonic Crystals and Plasmonics (META’14), Singapore, May 2014
  20. U. Beaskoetxea, M. Beruete, M. Zehar, A. Agrawal, S. Liu, K. Blary, A. Chahadih, X.-L. Han, M. Navarro-Cía, D. Etayo, A. Nahata, T. Akalin, and M. Sorolla Ayza, “Flat corrugated antennas in the THz,” 8th European Conf. on Antennas and Propag. 2014 (EuCAP2014), The Hague, The Netherlands, Apr. 2014
  21. O. Mitrofanov, M. Navarro-Cía, R. Mueckstein, M. Natrella, C. Graham, C.C. Renaud, A.J. Seeds, F. Dominec, P. Kužel, J.-C. Delagnes, P. Mounaix, “Surface plasmon waves for broadband THz spectroscopy,” SPIE Photonics West, San Francisco, U.S.A., Feb. 2014 (Invited)
  22. M. Navarro-Cía, M. Beruete, F. Falcone, M. Sorolla, and V. Lomakin, “Experimental Demonstration of Negative Group Delay on the Coupled Regime of Extraordinary Transmission Hole Arrays,” Metamaterials’ 2013, Bordeaux, France, Sept. 2013.
  23. M. Navarro-Cía, P. Rodríguez-Ulibarri, V. Torres, and M. Beruete, “Terahertz quarter-wave plate based on subwavelength hole arrays,” 7th European Conference on Antennas and Propagation 2013, EuCAP2013, Gothenburg, Sweden, Apr. 2013.
  24. V. Pacheco-Peña, V. Torres, M. Navarro-Cía, M. Beruete, M. Sorolla, N. Engheta, “ε-Near-Zero Graded Index Structure as a Bi-concave Metallic Lens Using Stacked Rectangular Near Cut-Off Waveguides,” 7th European Conference on Antennas and Propagation 2013, EuCAP2013, Gothenburg, Sweden, Apr. 2013.
  25. M. Zehar, M. Beruete, H. Sebai, H. Agnes, K. Blary, M. Navarro-Cía, and T. Akalin, “Fabrication of plasmonic arrays for THz QCL beam-shaping,” 5th International Workshop on Optical Terahertz Science and Technology 2013, OTST 2013, Kyoto, Japan, Apr. 2013.
  26. M. Beruete, T. Akalin, U. Beaskoetxea, M. Navarro-Cía, I. Arnedo, and M. Sorolla, “Extraordinary transmission corrugated antennas at THz,” 4th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META’13, Sharjah, United Arab Emirates, Mar. 2013 (Invited)
  27. V. Pacheco, V. Torres, M. Navarro-Cía, M. Beruete, M. Sorolla, and N. Engheta, “Plane-plane lenses using ε near-zero stacked waveguides at millimetre waves,” Metamaterials’2012, St. Petersburg, Russia, Sept. 2012.
  28. V. Torres, M. Navarro-Cía, M. Beruete, M. Sorolla, and N. Engheta, “Epsilon-near-zero waveguides for graded index lenses at terahertz frequencies,” IEEE AP-S International Symposium on Antennas and Propagation 2012 and USNC/URSI National Radio Science Meeting 2012 (2012 IEEE AP-S/URSI), Chicago, U.S.A., Jul. 2012.
  29. P. Rodríguez-Ulibarri, V. Torres, M. Beruete, and M. Navarro-Cía, “Dielectric-backed subwavelength hole arrays for terahertz polarization conversion,” IEEE AP-S International Symposium on Antennas and Propagation 2012 and USNC/URSI National Radio Science Meeting 2012 (2012 IEEE AP-S/URSI), Chicago, U.S.A., Jul. 2012.
  30. V. Torres, P. Rodriguez-Ulibarri, M. Beruete, F. Falcone, M. Sorolla, M. Navarro-Cía, “Tuning Extraordinary Transmission by Meander-Lines in Hole Arrays,” 4th International Conference Smart Materials, Structures, and Systems, CIMTEC 2012, Montecatini Terme, Tuscany, Italy, Jun. 2012
  31. S.A. Kuznetsov, M. A. Astafev, M. Navarro-Cía, A.V. Gelfand, and A.V. Arzhannikov, “Metamaterial-based holography for terahertz focusing: design, fabrication and experiment,” 3rd International Conference on Metamaterials, Photonic Crystals and Plasmonics, META’12, Paris, France, Apr. 2012
  32. S.A. Kuznetsov, A.V. Arzhannikov, M.K.A. Thumm, A.G. Paulish, A.V. Gelfand, V. N. Fedorinin, M. Beruete, M. Navarro-Cía, and M. Sorolla, “Ultrathin electromagnetic absorbers for mm- and submm-waves: from fundamentals towards applications in bolometric sensors,” 3rd International Conference on Metamaterials, Photonic Crystals and Plasmonics, META’12, Paris, France, Apr. 2012 (Invited)

7. Metal Mesh Filters

Led by Dr Fangjing Hu (Department of EEE)
Professor Stepan Lucyszyn, Dr William J. Otter, Jonathan Hazell (Department of EEE)
Dr Marco Ribeiro, ISCTE-IUL, Lisbon, Portugal

For ubiquitous THz systems using low-cost components, research into scalable metal mesh filters on electrically thick substrates is being undertaken. Shown below are two of these structures, the classic metal mesh filter and an improved trapped-mode design (having another complementary inner cross). These filters were realised using standard low-cost surface micromachining and measured using our turnkey TeraView 3000 terahertz time-domain spectroscopy (THz-TDS) system. The improved designs show good out-of-band rejection up to 3 THz, with narrow pass bands at the desired resonance frequencies from 0.1 to 0.5 THz. This work has led to the collaboration with Dr Marco Ribeiro from ISCTE-IUL (Lisbon, Portugal), with a €1.6k travel grant from COST Action MP1204, enabling work to design a low-cost THz stress sensor based on metal mesh structures. Other THz devices using metal mesh patterns, including modulators and absorbers, are also being investigated.

mesh
Conventional metal mesh filter (Left) and trapped-mode metal mesh filter (Right)

Conference Papers

  1. F. Hu, W. J. Otter and S. Lucyszyn, “Optically tunable THz frequency metamaterial absorber”, 40th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Hong Kong, China, Aug. 2015
  2. W. J. Otter, F. Hu, S. Lucyszyn and M. A. Ribeiro, “Prototype Design of THz Metallic Mesh Stress Sensor” MPNS COST Action MP1204 STSM Workshop, Warsaw, Poland, Nov. 2014.
  3. W. J. Otter, F. Hu, J. Hazell and S. Lucyszyn, “THz metal mesh filters on electrically thick fused silica substrates”, 39th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Tucson, USA, Sep. 2014
  4. W. J. Otter, F. Hu, J. Hazell and S. Lucyszyn, "From mm-wave to THz: scalable filter design for ultra-low cost applications", ARMMS RF & Microwave Society Conference, Nr Thame, Apr. 2014
  5. W. J. Otter, F. Hu and S. Lucyszyn, “Scalable metal mesh filters for low cost THz applications”, International Conference on Semiconductor Mid-IR Materials and Optics (SMMO2014), Marburg, Germany, Feb. 2014
  6. F. Hu, W. J. Otter and S. Lucyszyn, “THz metal mesh filters on thick fused silica substrate”, International Conference on THz and Mid Infrared Radiation and Applications to Cancer Detection using Laser Imaging, Workgroup Meetings of COST ACTIONs MP1204 and BM1205, Sheffield, UK, Oct. 2013

8. Photonic Crystals

Led by Dr William J. Otter (Department of EEE)
Professor Stepan Lucyszyn, Professor Andrew S. Holmes (Department of EEE)
Dr Stephen M. Hanham, Professor Norbert Klein (Department of Materials)
Nick Ridler, National Physical Laboratory (NPL)    

Photonic crystal research has focused on the design of the building blocks to create architectures for THz systems. Photonic crystals are an electromagnetic bandgap material engineered from a periodic variation in permittivity; in this case cylindrical air holes are made in high resistivity silicon (HRS) using bulk micromachining. As part of this work we have demonstrated waveguides, switches, attenuators and resonators. The resonators have shown state-of-the-art Q-factor performance, verified by traceable measurements at NPL. The use of resonators as a sensor is being investigated as part of the TERACELL project. Work to integrate the building blocks to create THz systems in ongoing to create a full photonic crystal front-end architecture.

pc

Photonic crystal filter (left) and attenuator (right)

Journal Paper

  1. S. M. Hanham, M. M. Ahmad S. Lucyszyn and N. Klein, “LED-switchable High-Q Packaged THz Microbeam Resonators,” IEEE Trans. Terahertz. Sci. Tech., accepted.
  2. S. M. Hanham, C. Watts, W. J. Otter, S. Lucyszyn and N. Klein, “Dielectric measurements of nanoliter liquids with a photonic crystal resonator at terahertz frequencies”, Applied Physics Letters, vol. 107, 032903, Jul. 2015
  3. W. J. Otter, S. M. Hanham, N. M. Ridler, G. Marino, N. Klein and S. Lucyszyn, “100 GHz ultra-high Q-factor photonic crystal resonators”, Sensors and Actuators A: Physical, Elsevier, vol. 217, pp. 151-159, Sep. 2014

Conference Papers

  1. W. J. Otter, S. M. Hanham, N. Klein and S. Lucyszyn, "Millimeter-wave negative group delay network," 2016 URSI Asia-Pacific Radio Science Conference, Seoul, Korea, 21-25 Aug. 2016.
  2. S. M. Hanham, W. J. Otter, S. Luscysyn and N. Klein, “Probing the THz Response of Biological Cells using Photonic Crystal Resonators,” Energy, Materials and Nanotechnology Meeting on Terahertz, San Sebastian, Spain, May 2016.
  3. W. J. Otter W, F. Hu, S. M. Hanham, A. S. Holmes, W. T. Pike, N. Klein, M. A. Riberio and S. Lucyszyn "Terahertz metamaterial devices," Int. Conf. on Semiconductor Mid-IR and THz Materials and Optics (SMMO2016), 2016.
  4. W. J. Otter, S. M. Hanham, N. M. Ridler, A. S. Holmes, N. Klein and S. Lucyszyn, “Terahertz photonic crystal technology”, Workshop on THz, Saint Petersburg, Russia, Jul. 2015
  5. W. J. Otter, S. M. Hanham, N. Klein, S. Lucyszyn and A. S. Holmes, “W-band laser-controlled photonic crystal variable attenuator”, IEEE International Microwave Symposium (IMS2014), Tampa Bay, USA, Jun. 2014
  6. W. J. Otter, S. M. Hanham, N. Ridler, A. S. Holmes, N. Klein and S. Lucyszyn, "MM-wave photonic crystal technology", IET Colloquium on Millimetre-wave and Terahertz Engineering & Technology, Liverpool, Mar. 2014
  7. W. J. Otter, S. M. Hanham, N. M. Ridler, A. S. Holmes, N. Klein and S. Lucyszyn, “100 GHz photonic crystal devices”, ARMMS RF & Microwave Society Conference, Wyboston, Nov. 2013 (Runner-up prize)
  8. W. J. Otter, S. M. Hanham, N. Ridler, A. S. Holmes, N. Klein and S. Lucyszyn, “Sub-THz photonic crystal devices”, International Conference on THz and Mid Infrared Radiation and Applications to Cancer Detection using Laser Imaging, Workgroup Meetings of COST ACTIONs MP1204 and BM1205, Sheffield, UK, Oct. 2013
  9. W. J. Otter, S. M. Hanham, E. Episkopou, Y. Zhou, N. Klein, A. S. Holmes and S. Lucyszyn, “Photoconductive photonic crystal switch”, 38th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz 2013), Mainz, Germany, Sep. 2013           
  10. W. J. Otter, S. M. Hanham, N. Klein and S. Lucyszyn, “Photonic Crystal Band Reject and Band Pass Filters”, MPNS COST Action Training School – MP1204, Cortona, Italy, May 2013

9. Biomedical Sensing

Led by Professor Norbert Klein (Department of Materials)
Dr Stephen M. Hanham, Clare Watts, Professor Molly Stevens (Department of Materials)
Professor Stepan Lucyszyn, Dr William J. Otter, Dr Munir Ahmad (Department of EEE)
Professor Stefan Maier, Dr Paloma Arroyo Huidobro (Department of Physics)
Professor Paul D. Abel, Professor Long R. Jiao (Department of Medicine)
Dr Nadia Guerra (Department of Life Sciences)

The spectrum of electromagnetic waves from the microwaves towards visible light offers a wide variety of complementary interaction mechanism with biomatter, which enables the development of a highly differentiated methodology for fingerprint detection of cells and biomolecules in a microfluidic environment. This includes cell membrane polarisation, bulk and hydration water dynamics, single and collective vibrational mode analysis and scattering. These enable the detection of global cell properties like size, water content and granularity, but also more specific chemical information related to the molecular content.

 Within the EPSRC funded project “TERACELL”, different types of microwave-to-terahertz resonator and transmission line structures have been investigated for highly sensitive liquid sensing in microfluidic systems. As a recent spin-out from these research activities, EVA Diagnostics (http://www.evadiagnostics.com/) was founded recently by a former PhD student of Prof. Klein. As the winner of the 2014 Oxbridge Biotech Roundtable OneStart competition, EVA Diagnostics is developing and commercializing electromagnetic blood analysis systems for point-of-care diagnostics.

 As a long term goal for our research, we believe that the complementarity of the information revealed from different regions of the electromagnetic spectrum will provide the scientific and technological basis for a new generation of point-of-care diagnostic instruments. We are working towards the ultimate and most comprehensive health check based on sole blood analysis; including infectious diseases, early-state-cancer diagnosis and monitoring of cancer treatment as well as early state detection of diseases like Alzheimer and Parkinson. 

bio

Two recent cover page journal articles published by the team: Electromagnetic anaemia detection by a microfluidics / microwave system (left) and THz liquid analysis by spoof plasmons

Journal Papers

  1. A. P. Gregory, J. F. Blackburn, K. Lees, R. N. Clarke, T. E. Hodgetts, S. M. Hanham, and N. Klein, “Measurement of the permittivity and loss of high-loss materials using a Near-Field Scanning Microwave Microscope,” Ultramicroscopy, vol. 161, pp. 137–145, Feb. 2016.
  2. S. M. Hanham, C. Watts, W. J. Otter, S. Lucyszyn and N. Klein, “Dielectric measurements of nanoliter liquids with a photonic crystal resonator at terahertz frequencies”, Applied Physics Letters, vol. 107, 032903, Jul. 2015
  3. B. Ng, S. M. Hanham, J. Wu, A. I. Fernandez-Dominguez, N. Klein, Y. F. Liew, M. B. H. Breese, M. Hong, S. A. Maier,  “Broadband Terahertz Sensing on Spoof Plasmon Surfaces,” ACS Photonics, vol. 1, pp. 1059-1067, Sep. 2014
  4. T. H. Basey-Fisher, N. Guerra, C. Triulzi, A. Gregory, S. M. Hanham, M. M. Stevens,  S. A. Maier and N. Klein,  “Microwaving Blood as a Non-Destructive Technique for Haemoglobin Measurements on Microlitre Samples,” Adv. Healthcare Mat., vol. 3, no. 4, pp. 536-542, Sep. 2013
  5. B. Ng, S. M. Hanham, J. Wu, A. I. Fernandez-Dominguez, N. Klein, Y. F. Liew, M. B. H. Breese, M. Hong, S. A. Maier,  “Spoof Plasmon Surfaces: A Novel Platform for THz Sensing, Adv. Opt. Mat., vol. 1, no. 8, pp. 543-548. Jun. 2013

 Conference Papers

  1. C. Watts, S. M. Hanham, M. Ahmad, M. Adabi and N. Klein, "Coupled dielectric-split ring microwave resonator for liquid measurements in microfluidic channels at nanoliter volumes," European Microwave, London, U.K., Oct. 2016.
  2. N. Klein, C. Watts, S. M. Hanham, W. J. Otter, A. Munir and S. Lucyszyn, "Microwave-to-terahertz dielectric resonators for liquid sensing in microfluidic systems," SPIE, San Diego, USA, Aug. 2016.
  3. S. M. Hanham, W. J. Otter, S. Luscysyn and N. Klein, “Probing the THz Response of Biological Cells using Photonic Crystal Resonators,” Energy, Materials and Nanotechnology Meeting on Terahertz, San Sebastian, Spain, May 2016.
  4. C. Watts, S. M. Hanham, N. Klein, "Towards microwave sensing of single cells", Biosensors 2016, Gothenburg Sweden, May 2016.
  5. A. P. Gregory, J. F. Blackburn, K. Lees, R. N. Clarke, T. E. Hodgetts, S. M. Hanham, and N. Klein, “A near-field scanning microwave microscope for measurement of the permittivity and loss of high-loss materials,” 84th ARFTG Microwave Measurement Conference 2014, Boulder, U.S.A., Dec. 2014 (Award Best Interactive Forum Paper)
  6. N. Klein, S. M. Hanham, T. H. Basey-Fisher, C. Watts, O. Shaforost, W. J. Otter and S. Lucyszyn, “Micro- and millimetre wave measurements of nanolitre biological liquids by dielectric resonators”, IEEE International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-Bio2014), London, pp. 90-92, Dec. 2014 (Invited)
  7. S. M. Hanham, M. Navarro-Cia, B. Ng, H. Aouani , M. Rahmani , N. Klein, S. A. Maier, Exploiting plasmonics for THz and infrared sensing,” Conference on Terahertz Physics, Devices, and Systems VIII - Advanced Applications in Industry and Defense, Publisher: SPIE-INT SOC OPTICAL ENGINEERING (Invited)
  8. N. Klein, T. H. Basey-Fisher, W. J. Otter, N. Guerra, C. Triulzi, A. Gregory, S. M. Hanham and S. Lucyszyn, "Towards microwave and millimeter wave biosensors," International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves (MSMW’13), Kharkov, Ukraine, pp. 510-511, Jun. 2013
  9. S. M. Hanham, A. Gregory, S. A. Maier, N. Klein, “A dielectric probe for near-field millimeter-wave imaging,” 37th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz 2012), Wollongong , Australia, Sep. 2012

 

10. THz Imaging With Strained-Si MODFET Sensors

Led by Dr Kristel Fobelets (Department of EEE)
Dr Y.M. Meziani, Dr J.E. Velázquez-Pérez, Universidad de Salamanca, Spain
Dr D. Coquillat, Dr W. Knap, CNRS-Université Montpellier 2, France

Strained-Si modulation doped field effect transistors (MODFETs) is used for non-resonant (broadband) and resonant detection of terahertz radiation. These MODFETs have a buried strained-Si channel with high electron concentration. The MODFETs are excited at room temperature by two types of terahertz sources (an electronic source based on frequency multipliers at 0.292 THz and a pulsed parametric laser at 1.5 THz). In both cases, a non-resonant response with maxima around the threshold voltage was observed. Shubnikov-de Haas and photoresponse measurements were performed simultaneously. These showed a phase-shift of  p/2 in good agreement with the theory, which demonstrates that the observed response is related to the plasma waves oscillation in the channel of the MODFET. The non-resonant features were used to demonstrate the capabilities of such devices in terahertz imaging. Cooling the MODFET down to 4.2 K increases the quality factor and resonant detection was observed by using a tuneable source of terahertz radiation.

modfet

Visible (left) and terahertz image (right) of a plastic box with a hidden mirror inside obtained using a strained-Si MODFET with gate length of 250 nm.

Journal Paper

  1. Y.M. Meziani, E. Garcia-Garcia, J.E. Velazquez-Perez, D. Coquillat, N. Dyakonova, W. Knap, I. Grigelionis, and K. Fobelets, “Terahertz Imaging Using Strained-Si MODFETs as Sensors”, Solid-State Electronics, vol. 83, pp 113-117, Feb. 2013

 Conference Papers

  1. J.A. Delgado-Notario, Y.M. Meziani, J.E. Velazquez-Perez, K. Fobelets, “Optimization of THz response of strained-Si MODFETs”, E-MRS Spring Meeting, Lille, France, May 2015
  2. Y.M. Meziani, J. E. Velazquez-Perez, D. Coquillat, N. Dyakonova, W. Knap, I. Grigelionis, E. Garcia-Garcia and K. Fobelets “Terahertz imaging using Si-SiGe MODFETS” Proc. Spanish Conf. on Electron Dev., Feb. 2013
  3. Y.M. Meziani, E. Garcia-Garcia, J.E. Velazquez-Perez, D. Coquillat, N. Dyakonova, W. Knap, I. Grigelionis, K. Fobelets, “Terahertz Imaging Using Strained-Si MODFETs as Sensors”, Silicon-Germanium Technology and Device Meeting (ISTDM), Berkeley, USA, Jun. 2012

11. Thermal Infrared ‘THz Torch’ (10-100 THz)

Led by Professor Stepan Lucyszyn (Department of EEE)
Dr Fangjing Hu, Jingye Sun, Dr William J. Otter, Rumessa Raja, Zouyiao Zou, Hanchao Lu (Department of EEE)
Dr Helen E. Brindley (Department of Physics)
Professor Anthony C. Chu (Department of Medicine)
Dr Xiaoxin Liang, Professor Yuepeng Yan, Chinese Academy of Sciences
Dr Zhengwei Wang, Sichuan Jiuzhou Electric Group Co.

The thermal infrared ‘THz Torch’ concept was first introduced by Lucyszyn et al. in 2011, for short-range secure wireless communications over a single (25 to 50 THz) channel. It fundamentally exploits engineered blackbody radiation, by partitioning thermally-generated spectral power into pre-defined frequency channels; the incoherent energy in each channel is then independently pulsed modulated. Within the past year, advances in the foundations, applications, source characterization and systems level analysis have been reported; incorporating frequency band multiplexing techniques across the 15 to 89 THz range. An up-to-date roadmap of the technology is shown below.

roadmap
Technology Roadmap for the Thermal Infrared ‘THz Torch’ Technology (Key publications indicated)

Low-cost Spectrometer for Early Skin Cancer Detection

The team have recently developed a general purpose spectrometer that operates in the thermal infrared part of the electromagnetic spectrum. Instead of employing sophisticated techniques – based around coherent sources, complex filter banks and cryogenically-cooled detectors – the team exploits the ‘THz Torch’ concept that employs low-cost commercial-off-the-shelf thermodynamic components. The result is a course, but effective, transmission-mode spectrometer that has already (through practical measurements) demonstrated its ability to identify dielectric materials from a database of pre-characterized thermal infrared spectral signatures, using robust statistical techniques.

The primary objective of a new 6-month project is to re-engineer the existing low-cost spectrometer for the sole purpose of early detection of skin cancers (as illustrated below); representing a totally new application for this technology. Since the thermal infrared has a relatively long wavelength it can penetrate the skin’s epidermis layer, where the complex dielectric permittivity of cancerous tissue contrasts against the background of normal skin tissue. The existing spectrometer has 16 matched pairs of band-pass filters; each filter pair providing a time-integrated spectral datum point. With 16 spectral data points, representing a course sampling of the thermal infrared (from 20 to 80 THz), the resulting signature can then be compared against a database of normal and abnormal skin tissue measurements.

spectrometer

Proposed low-cost spectrometer for early skin cancer detection

Journal Papers

  1. F. Hu, J. Sun, H. E. Brindley, X. Liang and S. Lucyszyn, “Systems analysis for thermal infrared 'THz Torch' applications”, Journal of Infrared, Millimeter, and Terahertz Waves, Springer, vol. 36, no. 5, pp. 474-495, May 2015
  2. F. Hu and S. Lucyszyn, “Modelling miniature incandescent light bulbs for thermal infrared 'THz Torch' applications”, Journal of Infrared, Millimeter, and Terahertz Waves, Springer, vol. 36, no. 4, pp. 350-367, Apr. 2015
  3. X. Liang, F. Hu, Y. Yan and S. Lucyszyn, “Secure thermal infrared communications using engineered blackbody radiation”, Scientific Reports, Nature Publishing Group, Sci. Rep. 4, 5245, Jun. 2014

 Book Chapter

  1. F. Hu and S. Lucyszyn, “Emerging thermal infrared ‘THz Torch’ technology for low-cost security and defence applications”, Chapter 13, pp. 239-275, “THz and Security Applications: Detectors, Sources and Associated Electronics for THz Applications, NATO Science for Peace and Security Series B: Physics and Biophysics, C. Corsi and F. Sizov (Editors), Springer Netherlands, ISBN: 978-94-017-8827-4, Apr. 2014

 Conference Papers

  1. S. Lucyszyn and F. Hu, “Secure thermal infrared ‘THz Torch’ communications”, 16th IEEE International Microwave and Optoelectronics Conference (IMOC 2015), Porto de Galinhas, Brazil, Nov. 2015 (Plenary)
  2. S. Lucyszyn and F. Hu, “Over the THz Horizon: The thermal infrared ‘THz Torch’”, 8th IEEE Global Symposium on Millimeter-Waves (GSMM2015), Montreal, Canada, May 2015 (Invited)
  3. J. Sun, F. Hu and S. Lucyszyn, "Challenges for the development of low cost thermal infrared 'THz Torch' spectrometers", 4th Annual Conference AnalytiX-2015, Nanjing, China, p. 216, Apr. 2015 (Invited)
  4. F. Hu and S. Lucyszyn, "Noise analysis for multi-channel ‘THz Torch’ thermal infrared wireless communications systems", Asia-Pacific Microwave Conference (APMC 2014), Sendai, Japan, pp.1276-1278, Nov. 2014
  5. F. Hu, X. Liang and S. Lucyszyn, "Multi-channel thermal infrared communications using engineered blackbody radiation for security applications", Conference SD114: Optics and Photonics for Counterterrorism, Crime Fighting and Defence, SPIE Security + Defence 2014, Amsterdam, The Netherlands, Sep. 2014
  6. F. Hu and S. Lucyszyn, "Thermal infrared communications", IoP Photon14, London, Sep. 2014
  7. X. Liang, F. Hu, Y. Yan and S. Lucyszyn, "Link budget analysis for secure thermal infrared communications using engineered blackbody radiation", XXXI General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS 2014), Beijing, China, Aug. 2014
  8. S. Lucyszyn and F. Hu, “THz torch technology for low-cost security applications”, NATO Conference 2013 on THz and Security Applications, Kiev, Ukraine, May 2013 (Invited)
  9. F. Hu and S. Lucyszyn, "Improved ‘THz torch’ technology for short-range wireless data transfer", IEEE International Wireless Symposium (IWS2013), Beijing, China, Apr. 2013
  10. F. Hu and S. Lucyszyn, “THz torch technologies for 21st century applications”, IoP Photon12, Durham, Sep. 2012
  11. F. Hu and S. Lucyszyn, “Ultra-low cost ubiquitous THz security systems”, Proc. of the 25th Asia-Pacific Microwave Conference (APMC2011), Melbourne, Australia, pp. 60-62, Dec. 2011 (Invited)
  12. S. Lucyszyn, H. Lu and F. Hu, “Ultra-low cost THz short-range wireless link”, IEEE International Microwave Workshop Series on Millimeter Wave Integrated Technologies (IMWS 2011), Sitges, Spain, pp. 49-52, Sep. 2011

12. Low-loss Quasi-Optical Multiplexer (QOM)

Led by Dr Richard J. Wylde FREng (TK Instruments)
Dr Stephen M. Hanham (Department of Materials)
Dr William J. Otter (Department of EEE)
Kevin Pike, Stuart Froud, Adam Woodcraft, TK Instruments
Professor Peter A. Ade, Professor Carole Tucker, Amber Hornsby,
School of Physics and Astronomy, Cardiff University
Lifei Jiang, Zhenchao Xie, Hongxin Xu, Shanghai Aerospace Electronic Technology Institute, CASC

A low-loss quasi-optical multiplexer (QOM) for future space-based meteorological radiometry covering nearly a decade bandwidth (from 54 GHz to 425 GHz), was developed by TK instruments. The losses in the multiplexer were measured using a novel double path S11 VNA technique, and beam co-alignment was verified by scanning with a wideband detector using the measurement facilities within the CTSE laboratory at Imperial. The results showed that very low loss can be combined with high channel co-alignment in a compact package, suitable for surviving the launch environment.

tk

The doubled layered QOM, with Cu-coloured DCPs on the top layer with the VNA head in the top right of the picture

Conference Paper

  1. R. J. Wylde, P. A. Ade, S. Froud, S. M. Hanham, A. Hornsby, L. Jiang, W. J. Otter, K. Pike, C. Tucker, A. Woodcraft, Z. Xie and H. Xu, “The design, construction and measurement of a quasi-optical multiplexer and antenna for space-borne atmospheric measurements from 56 to 425 GHz”, 40th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Hong Kong, China, (Submitted 20th Mar. 2015)       

13. Other Publications

Journal Papers

  1. S. Papantonis, N. M. Ridler, A. Wilson and S. Lucyszyn, “Reconfigurable waveguide for vector network analyzer verification”, IEEE Transactions on Microwave Theory and Techniques, vol. 62, no. 10, pp. 2415-2422, Oct. 2014
  2. K. Choonee and R. R. A. Syms, “Robust cylindrical plasmonic nano-antennas for light-matter interaction,” Progress In Electromagnetics Research, Vol. 148, pp. 129-139, Jul. 2014
  3. Syms R.R.A., Solymar L. “Loss and thermal noise in plasmonic waveguides” J. Appl. Phys., Vol. 115, Jun. 2014
  4. K. Choonee, R. R. A. Syms “Folded dipole plasmonic resonators” Optics Express, vol. 21, no. 22, pp. 25841-25840, Nov. 2013
  5. E. Episkopou, S. Papantonis, W. J. Otter and S. Lucyszyn, "Defining material parameters in commercial EM solvers for arbitrary metal-based THz structures”, IEEE Transactions on Terahertz Science and Technology, vol. 2, no. 5, pp. 513-524, Sep. 2012

Conference Papers

  1. A. P. Gregory, J. F. Blackburn, K. Lees, R. N. Clarke, T. E. Hodgetts, S. M. Hanham, and N. Klein, “A near-field scanning microwave microscope for measurement of the permittivity and loss of high-loss materials,” 84th ARFTG Microwave Measurement Conference, 2014 (Best Interactive Forum Paper Award)
  2. S. Papantonis, N. M. Ridler and S. Lucyszyn, “A new technique for vector network analyzer calibration verification using a single reconfigurable device”, 82nd ARFTG Conference, Columbus, USA, Nov. 2013
  3. S. Lucyszyn, F. Hu and W. J. Otter, “Technology demonstrators for low-cost terahertz engineering”, Asia-Pacific Microwave Conference (APMC 2013), Seoul, South Korea, pp. 518-520, Nov. 2013 (Invited)
  4. E. Episkopou, S. Papantonis, A. S. Holmes and S. Lucyszyn, "Optically-controlled plasma switch for integrated terahertz applications", 39th IEEE International Conference on Plasma Science (ICOPS2012), Edinburgh, Jul. 2012
  5. S. Lucyszyn and Y. Zhou, “Reconfigurable terahertz integrated architecture (RETINA) – a paradigm shift in SIW technology”, IEEE International Microwave Symposium (IMS2012) Workshop Proceedings, WFA: Integration and Technologies for mm-Wave Sub-systems, Montreal, Canada, Jun. 2012 (Invited)
  6. E. Episkopou, S. Papantonis, W. J. Otter and S. Lucyszyn, "Demystifying material parameters for terahertz electromagnetic simulation", 4th UK/Europe-China Conference on Millimetre Waves and Terahertz Technologies, Glasgow, pp. 80-81, Sep. 2011