Terahertz wave presenations

Towards large area THz electromagnetic metamaterials (Paper Presentation)
Paper 7029-12 of Conference 7029
Authors(s): Herbert O. Moser, National Univ. of Singapore (Singapore)
Date: Sunday, 10 August 2008
Up to date, metamaterials have been mostly produced by primary pattern generation via e-beam or laser which is time-consuming and may yield only limited useful areas. Particularly, e-beam writing may only cover some 100×100 μm2. However, many applications require larger quantities of good quality materials. Since 2002, SSLS has been using its X-ray-lithography-based LIGA process to micro/nanomanufacture a variety of high-aspect-ratio metamaterials structures. Split-ring designs have led to resonance frequencies from 1 - 216 THz. Meanwhile, stringlike structures have also been included. Latest progress in the manufacturing and characterization of 1 cm2 quasi-3D metamaterials structures will be described.

Surface-plasmon-polariton-enhanced reflected THz-field (Paper Presentation)
Paper 7065-3 of Conference 7065
Authors(s): Dan-Hong Huang, Air Force Research Lab.; Godfrey A. Gumbs, Hunter College/CUNY; Paul M. Alsing, David A. Cardimona, Air Force Research Lab.
Date: Monday, 11 August 2008
The present work predicts the large enhancements at the band edges of a coupled Bloch-surface-plasmon-polariton band in the spectrum of the reflected far electromagnetic field due to anti-crossing gaps induced by the strong coupling between the continuous surface-plasmonpolariton mode and the discrete Bloch-like modes. The existence of these Bloch-like modes is a direct consequence of the nonlocal mixing of specular and diffraction modes of the reflected electromagnetic field by free-electron induced optical polarization and the interference of a pair of surface optical-polarization waves with opposite Bragg order numbers in the presence of a grating.

THz generation by X(3) media (Poster Presentation)
Paper 7056-48 of Conference 7056
Authors(s): Shizhuo Yin, Meng-Ku Chen, Peng Li, The Pennsylvania State Univ.
Date: Tuesday, 12 August 2008
In this paper, we review the THz generation in X(3) media via the third order nonlinear effects. For example, THz wave has been successfuly generated by the air plasma via the third order nonlinear effects by several groups around the world. Besides the air plasma in the free space form, the air plasma in a confined structure (e.g., metal waveguides, photonic crystal waveguides) and the possibility of generating THz wave in other types of isotropic media (e.g., glasses) are also investigated.

Plasmon mediated InGaAs/InP tunable far-IR detector (Paper Presentation)
Paper 7082-8 of Conference 7082
Authors(s): Walter R. Buchwald, Air Force Research Lab.; Himanshu Saxena, Robert E. Peale, Univ. of Central Florida
Date: Monday, 11 August 2008
This work presents an experimental investigation of a THz detector based on plasmon excitation in the two dimensional electron gas of a high electron mobility transistor. This device, fabricated from the InGaAs/InP material system, relies on e-beam lithography to fabricate a gate in the form of a grating with sub-micron period. Sensitivity of the device conductance to incident THz fields is reported. Direct absorption of THz radiation, temperature effects, and the effects of source to drain current on system performance are also investigated. It is expected that this class of device will find use in spaceborne remote sensing applications.

Heterodyne receivers based on an NbN hot electron bolometer mixer and a quantum cascade laser as local oscillator above 2 THz (Paper Presentation)
Paper 7082-18 of Conference 7082
Authors(s): Pourya Khosropanah, SRON Netherlands Institute for Space Research (Netherlands); Wen Zhang, Purple Mountain Observatory (China) and SRON Netherlands Institute for Space Research (Netherlands); Jian-Rong Gao, SRON Netherlands Institute for Space Research (Netherlands) and Technische Univ. Delft (Netherlands); J. Niels Hovenier, Technische Univ. Delft (Netherlands); Wouter M. Laauwen, SRON Netherlands Institute for Space Research (Netherlands); Merlijn Hajenius, Technische Univ. Delft (Netherlands) and SRON Netherlands Institute for Space Research (Netherlands); Teun M. Klapwijk, Technische Univ. Delft (Netherlands)
Date: Tuesday, 12 August 2008
Future space borne or airborne heterodyne receivers will target frequency range of 2-6 THz, which holds crucial information on astronomical objects as well as on chemical composition of Earth’s atmosphere. Here we highlight the progress on heterodyne receivers above 2 THz. This includes our latest result i.e. 2100 K double side band receiver noise temperature at 3.5 THz using a distributed feedback (DFB) QCL as LO and an HEB mixer integrated with spiral antenna. We also discuss suitability of such a QCL as an LO in a real space instrument in terms of beam pattern, power consumption and stability.

Terahertz conductivity measurements in films of semiconductor and metallic single walled carbon nanotubes. (Paper Presentation)
Paper 7034-21 of Conference 7034
Authors(s): Matthew C. Beard, Michael J. Heben, Jeffery Blackburn, National Renewable Energy Lab.
Date: Tuesday, 12 August 2008
We report the frequency-dependent complex conductivity in the far-infrared for a series of single walled carbon nanotube (SWCNT) films where the ratio of metallic to semiconductor tube types has been systematically varied. We studied films of 6.2, 23.5, 29.5, 57.9, 93.1, and 97.8% metallic tube content. In addition we explored the effect on the THz conductivity when films are subsequently p-doped by treating with thionel chloride. We find that the real part of the conductivity increases with increasing frequency and the imaginary part is negative. This phenomenon is characteristic of materials that have a suppressed long range transport due to disorder or materials that exhibit stochastic transport. We analyze the results by using a Drude-Smith conductivity model at low frequencies and a lorenzitian oscillator at higher frequencies. We find that extracted dc conductivity from the ac (THZ) measurements compare favorably to a four-point-probe measurement.

Optical studies of plasmonic metamaterials (Paper Presentation)
Paper 7033-49 of Conference 7033
Authors(s): Valy Z. Vardeny, The Univ. of Utah
Date: Wednesday, 13 August 2008
Extraordinary optical transmission (EOT) through periodic and aperiodic arrays of subwavelength apertures is an example of metamaterial media. The subwavelength nature of the active surface plasmon polariton (SPP) excitations, along with strong field localization in these structures open up novel applications in bio-sensing, guided-wave devices and quantum optics. Our work has been primarily focused on the fundamental investigation and development of two-dimensional (2D) plasmonic metamaterials that are active in the visible, infrared and terahertz (THz) frequencies. Using pump-probe spectroscopy we investigated the transient response of photoexcited SPP excitations. Also using THz time-domain spectroscopy we measured the transmission properties of periodic and aperiodic aperture arrays.

Frontside-illuminated quantum well photodetector for far-infrared range (Paper Presentation)
Paper 7055B-21 of Conference 7055B
Authors(s): Mikhail A. Patrashin, Iwao Hosako, National Institute of Information and Communications Technology (Japan)
Date: Monday, 11 August 2008
We have demonstrated the operation of a frontside-illuminated GaAs/AlGaAs quantum well photodetector based on intersubband absorption in a quantum well (QW) with a targeted peak frequency of 3 THz. A multiple quantum well structure consists of 20 periods of 18 nm QWs interleaved by 80 nm barriers with an Al alloy content of 2%. We measured the following performance characteristics: dark current, responsivity, and spectral response. We looked also at possible designs to optimize the device’s performance.

Frequency dependence of the observed phase transition in nanostructured and doped VO2 thin films (Paper Presentation)
Paper 7041-18 of Conference 7041
Authors(s): Geoffrey B. Smith, Angus R. Gentle, Univ. of Technology/Sydney (Australia)
Date: Thursday, 14 August 2008
The nature of the phase transition in doped and nano-VO2 is shown to depend on the frequency at which it is observed. A transient correlated insulator is seen above Tc at frequencies under THz, while it appears metallic and uncorrelated at optical frequencies.

Trapping light without double negative index metamaterials for all frequencies (Paper Presentation)
Paper 7029-19 of Conference 7029
Authors(s): Wen-Tao Lu, Northeastern Univ.
Date: Monday, 11 August 2008
Recently, Tsakmakidis et al (Nature 450, 397 (2007)) proposed to use double negative index waveguide to trap light. In this talk, I propose different schemes to trap light in planar and cylindrical waveguide structures without the use of double negative index metamaterials. For frequencies ranged from microwaves, THz waves, and up to the visibles, different feasible realizations are provided and verified by numerical simulations. Our experimental results on trapping and slow light will also be discussed.

Surface plasmon localization for the optical control of field emission (Paper Presentation)
Paper 7037-26 of Conference 7037
Authors(s): Pierrick Guiset, Sylvain Combrie, Mathieu Carras, Alfredo De Rossi, Jean-Philippe P. Schnell, Pierre Legagneux, Thales Research & Technology (France)
Date: Tuesday, 12 August 2008
We present the first steps for the validation of an optically driven field emission cathode. This approach relies on the interaction of surface plasmons with vertically aligned multi-wall carbon nanotubes or metallic nanowires arrays. The objective is to modulate the field emission current by using the optical component at the field emitter apex through antenna coupling. Thanks to metallic surface cavities, surface plasmons will be generated and localized in the vicinity of nanoemitters to improve interaction efficiency. First simulations and experimental measurements will be presented jointly with perspectives for the wideband modulation of electronic beams till THz.

Terahertz wave propergation in structured metals (Paper Presentation)
Paper 7033-31 of Conference 7033
Authors(s): Masanori Hangyo, Keisuke Takano, Kyoji Shibuya, Osaka Univ. (Japan); Fumiaki Miyamaru, Shinshu Univ. (Japan); Hiroshi Miyazaki, Tohoku Univ. (Japan)
Date: Tuesday, 12 August 2008
Electromagnetic wave propagation in structured metals has attracted strong attention in wide wavelength regions from microwave to visible. We have investigated transmission properties of metal hole arrays in the terahertz region by using the terahertz time-domain spectroscopy (THz-TDS). We have found variety of transmission properties depending on the periodic structure of metals, i. e. extraordinary transmission, large polarization conversion, and large optical activity, etc. Some of the properties are explained by the surface plasmon-polariton and the local structure of holes.

Theoretical studies of defect states in GaSe and GaTe (Paper Presentation)
Paper 7079-26 of Conference 7079
Authors(s): Zsolt Rak, S. D. Mahanti, Michigan State Univ.; Krishna C. Mandal, EIC Labs., Inc.; Nils C. Fernelius, Air Force Research Lab.
Date: Tuesday, 12 August 2008
GaSe and GaTe are promising materials for radiation detectors and various opto-electronic devices including time-domain terahertz spectroscopy (TDTS), broadband tunable terahertz (THz) sources and detectors. In all these applications charge carrier creation and transport play crucial roles. Electrical, optical and transport properties of semiconductors are strongly affected by defects. In order to understand the nature of defect states in these semiconductors we have carried out ab initio studies using density functional theory and supercell model. Theoretical binding energy values for a series of defects in GaSe and GaTe are calculated and found to be in good agreement with the experimental result.

From nano to meta: plasmonic waveguides and their characterization in different parts of the spectrum (Paper Presentation)
Paper 7032-55 of Conference 7032
Authors(s): Stefan A. Maier, Imperial College (United Kingdom)
Date: Wednesday, 13 August 2008
This talk will present both design principles for plasmonic waveguides offering sub-wavelength scale mode confinement working in different parts of the spectrum, and important techniques for their experimental characterization. Examples will be drawn from plasmon waveguides working at visible frequencies, where sub-wavelength energy localization is achieved via intrinsic effects. At lower frequencies, a metamaterial approach is needed to engineer spoof surface plasmon polaritons modes with effective plasma frequencies controlled by the surface geometry alone. Numerical results as well as experimental demonstrations of waveguides operating in at visible and at THz frequencies will be discussed, and their properties assessed.

Ultrafast local investigations of plasmonic structures (Paper Presentation)
Paper 7032-59 of Conference 7032
Authors(s): Laurens Kuipers, FOM Institute for Atomic and Molecular Physics (Netherlands)
Date: Wednesday, 13 August 2008
Both plasmonic and periodic structures can exert a huge control over electromagnetic waves at the nanoscale. The result may be slow light in photonic crystal waveguides or huge field enhancements near metal nanostructures. With plasmonic crystals we gain the best of both worlds. Visualization of the propagation with subwavelength resolution allows the optical properties to be unravelled in detail. With a time-resolved near-field microscope we have tracked plasmonic wavepackets (duration 100 fs) as they propagate. We show that plasmons in periodic structures obey Bloch's theorem. Moreover, we can slow the wavepackets down for their entire bandwidth (~4 THz).

Terahertz plasmonic energy concentration (Paper Presentation)
Paper 7029-22 of Conference 7029
Authors(s): Mark I. Stockman, Maxim Durach, Anastasia Rusina, Georgia State Univ.
Date: Monday, 11 August 2008
We present theory of subwavelength terahertz spoofed plasmonics. We propose an approach to highly efficient concentration of the terahertz oscillation energy on a deep subwavelength scale using metamaterials structures. Efficient metal-dielectric structures structures are presented that allow for subwavelength focusing of terahertz waves to ~0.01 of the vacuum wavelength. Wide range of applications are possible and discussed.

Terahertz wave propergation in structured metals (Paper Presentation)
Paper 7033-31 of Conference 7033
Authors(s): Masanori Hangyo, Keisuke Takano, Kyoji Shibuya, Osaka Univ. (Japan); Fumiaki Miyamaru, Shinshu Univ. (Japan); Hiroshi Miyazaki, Tohoku Univ. (Japan)
Date: Tuesday, 12 August 2008
Electromagnetic wave propagation in structured metals has attracted strong attention in wide wavelength regions from microwave to visible. We have investigated transmission properties of metal hole arrays in the terahertz region by using the terahertz time-domain spectroscopy (THz-TDS). We have found variety of transmission properties depending on the periodic structure of metals, i. e. extraordinary transmission, large polarization conversion, and large optical activity, etc. Some of the properties are explained by the surface plasmon-polariton and the local structure of holes.

Plasmonic metamaterials and their applications in novel terahertz devices (Paper Presentation)
Paper 7033-52 of Conference 7033
Authors(s): Taiichi Otsuji, Tohoku Univ. (Japan)
Date: Wednesday, 13 August 2008
[Invited] “Metamaterial” is one of the emerging science and engineering regions where new paradigm of manipulating electromagnetic waves from microwaves to beyond optical waves in various extraordinary ways are just now being born. This presentation reviews recent advances in terahertz electromagnetic metamaterials. In particular, the topics will be focused on plasmonic metamaterials where material- and structure-dependent highly dispersive systems are configured in submicron-to-nanometer scaled artificial dimensions to perform emission, detection, and moreover higher functional signal processing like intensity modulation as well as frequency multiplication in an exploring terahertz frequency region.

Near-field studies of surface plasmon generation: optical and terahertz studies (Paper Presentation)
Paper 7032-63 of Conference 7032
Authors(s): Dai-sik Kim, Hyun Woo Kihm, Kwang-Geol Lee, Min Ah Seo, Seoul National Univ. (South Korea); A. J. L. Adam, Technische Univ. Delft (Netherlands); JiHoon Kang, Korea Univ. (South Korea); Kwang Jun Ahn, Seoul National Univ. (South Korea); Q-Han Park, Korea Univ. (South Korea); P.C.M. Planken, Technische Univ. Delft (Netherlands)
Date: Wednesday, 13 August 2008
We study the dielectric constant dependent diffraction phenomena of single slit aperture, both theoretically and experimentally. We experimentally simulate the perfect metal and a real metal cases by investigating sub-wavelength diffraction by a single slit, both in nano-optical and in terahertz regimes keeping the slit-width/wavelength ratio approximately the same for both of frequency regimes. The wave-front in optical regime separates itself into forward propagating beam and surface-bound 90-degree diffracted wave, i.e., surface plasmon polaritons; while separation of modes is not observed in terahertz regime.

Terahertz conductivity measurements in films of semiconductor and metallic single walled carbon nanotubes. (Paper Presentation)
Paper 7034-21 of Conference 7034
Authors(s): Matthew C. Beard, Michael J. Heben, Jeffery Blackburn, National Renewable Energy Lab.
Date: Tuesday, 12 August 2008
We report the frequency-dependent complex conductivity in the far-infrared for a series of single walled carbon nanotube (SWCNT) films where the ratio of metallic to semiconductor tube types has been systematically varied. We studied films of 6.2, 23.5, 29.5, 57.9, 93.1, and 97.8% metallic tube content. In addition we explored the effect on the THz conductivity when films are subsequently p-doped by treating with thionel chloride. We find that the real part of the conductivity increases with increasing frequency and the imaginary part is negative. This phenomenon is characteristic of materials that have a suppressed long range transport due to disorder or materials that exhibit stochastic transport. We analyze the results by using a Drude-Smith conductivity model at low frequencies and a lorenzitian oscillator at higher frequencies. We find that extracted dc conductivity from the ac (THZ) measurements compare favorably to a four-point-probe measurement.

Theoretical studies of defect states in GaSe and GaTe (Paper Presentation)
Paper 7079-26 of Conference 7079
Authors(s): Zsolt Rak, S. D. Mahanti, Michigan State Univ.; Krishna C. Mandal, EIC Labs., Inc.; Nils C. Fernelius, Air Force Research Lab.
Date: Tuesday, 12 August 2008
GaSe and GaTe are promising materials for radiation detectors and various opto-electronic devices including time-domain terahertz spectroscopy (TDTS), broadband tunable terahertz (THz) sources and detectors. In all these applications charge carrier creation and transport play crucial roles. Electrical, optical and transport properties of semiconductors are strongly affected by defects. In order to understand the nature of defect states in these semiconductors we have carried out ab initio studies using density functional theory and supercell model. Theoretical binding energy values for a series of defects in GaSe and GaTe are calculated and found to be in good agreement with the experimental result.

Optical studies of plasmonic metamaterials (Paper Presentation)
Paper 7033-49 of Conference 7033
Authors(s): Valy Z. Vardeny, The Univ. of Utah
Date: Wednesday, 13 August 2008
Extraordinary optical transmission (EOT) through periodic and aperiodic arrays of subwavelength apertures is an example of metamaterial media. The subwavelength nature of the active surface plasmon polariton (SPP) excitations, along with strong field localization in these structures open up novel applications in bio-sensing, guided-wave devices and quantum optics. Our work has been primarily focused on the fundamental investigation and development of two-dimensional (2D) plasmonic metamaterials that are active in the visible, infrared and terahertz (THz) frequencies. Using pump-probe spectroscopy we investigated the transient response of photoexcited SPP excitations. Also using THz time-domain spectroscopy we measured the transmission properties of periodic and aperiodic aperture arrays.

Package inspection using inverse diffraction (Paper Presentation)
Paper 7072-16 of Conference 7072
Authors(s): Alastair D. McAulay, Lehigh Univ.
Date: Wednesday, 13 August 2008

1040 nm

PCA with LT-GaAs absorber for laser excitation wavelengths λ ~ 1040 nm; optical resonant design 97% absorption @ 1040 nm

Cortes 800 tabletop 40 TW Ti:Sapphire laser system
Cortes E - High vacuum laser ablation/deposition system with 2 TW Ti:Sapphire laser
Cortes K - femtosecond seed laser for Petawatt KrF excimer laser
Cortes O 200TW femtosecond laser - KD*P CPOPA based amplifier system
Jaws femtosecond Cr:forsterite Multi-Terawatt Amplified Laser
High-vacuum system for laser ablation/deposition

Reef scanning and single shot femtosecond autocorrelators
Avoca SPIDER - Spectral phase interferometry for direct electric-field reconstruction (SPIDER)
Rincon third order femtosecond cross-correlator (third order autocorrelator TOAC) also referred to as contrastmeter

Beacon femtosecond fluorescence up-conversion (optical gating) spectrometer
Hatteras Ultrafast Transient Absorption Spectrometer

Model	Product Name+	Price	Buy Now
PCA-44-16-16-800-u	PCA: resonance frequency 1 THz, λ = 800 nm, gap distance 16 µm	$825.00
PCA-44-16-16-800-h	PCA: resonance frequency 1 THz, λ = 800 nm, gap distance 16 µm	$1,950.00
PCA-44-34-100-800-u	PCA: resonance frequency 1 THz, λ = 800 nm, gap distance 34 µm	$825.00
PCA-44-34-100-800-h	PCA: resonance frequency 1 THz, λ = 800 nm, gap distance 34 µm	$1,950.00
PCA-44-06-10-800-u	PCA: resonance frequency 1 THz, λ = 800 nm, gap distance 6 µm	$825.00
PCA-44-06-10-800-h	PCA: resonance frequency 1 THz, λ = 800 nm, gap distance 6 µm	$1,950.00
PCA-30-10-10-800-u	PCA: resonance frequency 1.5 THz, λ = 800 nm, gap distance 10 µm	$825.00
PCA-30-10-10-800-h	PCA: resonance frequency 1.5 THz, λ = 800 nm, gap distance 10 µm	$1,950.00
PCA-30-14-14-800-u	PCA: resonance frequency 1.5 THz, λ = 800 nm, gap distance 14 µm	$825.00
PCA-30-14-14-800-h	PCA: resonance frequency 1.5 THz, λ = 800 nm, gap distance 14 µm	$1,950.00

Model	Product Name+	Price	Buy Now
PCA-44-16-16-1030-h	PCA: resonance frequency 1 THz, λ = 990 .. 1060 nm, gap distance 16 µm	$1,950.00
PCA-44-16-16-1030-u	PCA: resonance frequency 1 THz, λ = 990 .. 1060 nm, gap distance 16 µm	$825.00
PCA-44-34-100-1030-u	PCA: resonance frequency 1 THz, λ = 990 .. 1060 nm, gap distance 34 µm	$825.00
PCA-44-34-100-1030-h	PCA: resonance frequency 1 THz, λ = 990 .. 1060 nm, gap distance 34 µm	$1,950.00
PCA-44-06-10-1030-u	PCA: resonance frequency 1 THz, λ = 990 .. 1060 nm, gap distance 6 µm	$825.00
PCA-44-06-10-1030-h	PCA: resonance frequency 1 THz, λ = 990 .. 1060 nm, gap distance 6 µm	$1,950.00
PCA-30-10-10-1030-h	PCA: resonance frequency 1.5 THz, λ = 990 .. 1060 nm, gap distance 10 µm	$1,950.00
PCA-30-10-10-1030-u	PCA: resonance frequency 1.5 THz, λ = 990 .. 1060 nm, gap distance 10 µm	$825.00
PCA-30-14-14-1030-u	PCA: resonance frequency 1.5 THz, λ = 990 .. 1060 nm, gap distance 14 µm	$825.00
PCA-30-14-14-1030-h	PCA: resonance frequency 1.5 THz, λ = 990 .. 1060 nm, gap distance 14 µm	$1,950.00

Model	Product Name+	Price	Buy Now
PCA-44-16-16-1040-h	PCA: resonance frequency 1 THz, λ ~ 1040 nm, gap distance 16 µm	$1,950.00
PCA-44-16-16-1040-u	PCA: resonance frequency 1 THz, λ ~ 1040 nm, gap distance 16 µm	$825.00
PCA-44-34-100-1040-h	PCA: resonance frequency 1 THz, λ ~ 1040 nm, gap distance 34 µm	$1,950.00
PCA-44-34-100-1040-u	PCA: resonance frequency 1 THz, λ ~ 1040 nm, gap distance 34 µm	$825.00
PCA-44-06-10-1040-h	PCA: resonance frequency 1 THz, λ ~ 1040 nm, gap distance 6 µm	$1,950.00
PCA-44-06-10-1040-u	PCA: resonance frequency 1 THz, λ ~ 1040 nm, gap distance 6 µm	$825.00
PCA-30-10-10-1040-u	PCA: resonance frequency 1.5 THz, λ ~ 1040 nm, gap distance 10 µm	$825.00
PCA-30-10-10-1040-h	PCA: resonance frequency 1.5 THz, λ ~ 1040 nm, gap distance 10 µm	$1,950.00
PCA-30-14-14-1040-h	PCA: resonance frequency 1.5 THz, λ ~ 1040 nm, gap distance 14 µm	$1,950.00
PCA-30-14-14-1040-u	PCA: resonance frequency 1.5 THz, λ ~ 1040 nm, gap distance 14 µm	$825.00

Model	Product Name+	Price	Buy Now
iPCAp-21-05-1000-800	iPCAp, 800 nm, 21x5x1000 microns	$2,880.00
iPCAp-21-05-300-800-	iPCAp, 800 nm, 21x5x300 microns	$2,720.00
iPCAs-21-05-1000-800	iPCAs, 800 nm, 21x5x1000 microns	$2,880.00
iPCAs-21-05-300-800-	iPCAs, 800 nm, 21x5x300 microns	$2,720.00

800 nm

PCA with LT-GaAs absorber for laser excitation wavelengths λ ≤ 850 nm; optical absorption > 70%

990-1060 nm

PCA with LT-GaAs absorber for laser excitation wavelengths λ = 990 .. 1060 nm; optical absorption ~ 50%

iPCA

interdigital Photoconductive Antenna for terahertz waves