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For measurements designed to accurately determine layer thickness, there is a natural trade-off between sensitivity to optical thickness and lateral resolution due to the angular ray distribution required for a focused beam. We demonstrate…

We report bilayer-graphene field effect transistors operating as THz broadband photodetectors based on plasma-waves excitation. By employing wide-gate geometries or buried gate configurations, we achieve a responsivity $\sim 1.2V/W (1.3…

The common terahertz time-domain spectroscopy (THz-TDS) based on photoconductive antenna (PCA) needs two separate PCA chips. One PCA works as an emitter, and the other works as a receiver. For a reflection-type measurement, the technique…

Optics · Physics 2013-12-17 Jitao Zhang

In this paper, a wideband and low-scattering metasurface in terahertz (THz) is introduced. The proposed coding metasurface is composed of four different graphene square patches in one layer, which has a distinct bias voltage. By optimizing…

Applied Physics · Physics 2020-01-28 Kasra Rouhi , Ali Abdolali , Susan Fallah

Spintronic terahertz emitters promise terahertz sources with an unmatched broad frequency bandwidth that are easy to fabricate and operate, and therefore easy to scale at low cost. However, current experiments and proofs of concept rely on…

Terahertz (THz) technology has been a great candidate for applications, including pharmaceutic analysis, chemical identification, and remote sensing and imaging due to its non-invasive and non-destructive properties. Among those…

Signal Processing · Electrical Eng. & Systems 2022-04-05 Chia-Hsiang Lin , Yi-Chun Hung , Feng-Yu Wang , Shang-Hua Yang

Infrared imaging is indispensable for its ability to penetrate obscurants and visualize thermal signatures, yet its practical use is hindered by the intrinsic limitations of conventional detectors. Nonlinear upconversion, which converts…

Computational imaging modalities support a simplification of the active architectures required in an imaging system and these approaches have been validated across the electromagnetic spectrum. Recent implementations have utilized…

Classical Physics · Physics 2016-08-24 Thomas Fromenteze , Xiaojun Liu , Michael Boyarsky , Jonah Gollub , David R. Smith

We propose a high resolution spatial diagnostic method via inserting a millimeter-gap grating into the collimated terahertz beam to monitor the minute variation of the terahertz beam in strong-field terahertz sources, which is difficult to…

A laser pulse composed of a fundamental and an appropriately phased second harmonic can drive a time-dependent current of photoionized electrons that generates broadband THz radiation. Over the propagation distances relevant to many…

Terahertz (THz) systems have the benefit of high bandwidth and hence are capable of supporting ultra-high data rates, albeit at the cost of high pathloss. Hence they tend to harness high-gain beamforming. Therefore a novel hybrid 3D…

Signal Processing · Electrical Eng. & Systems 2022-02-07 Xufang Wang , Zihuai Lin , Feng Lin , Lajos Hanzo , Life Fellow

In this paper, we consider the imaging problem of terahertz (THz) tomography, in particular as it appears in non-destructive testing. We derive a nonlinear mathematical model describing a full THz tomography experiment, and consider linear…

Numerical Analysis · Mathematics 2020-10-29 Simon Hubmer , Alexander Ploier , Ronny Ramlau , Peter Fosodeder , Sandrine van Frank

Coherent X-ray diffraction microscopy is a method of imaging non-periodic isolated objects at resolutions only limited, in principle, by the largest scattering angles recorded. We demonstrate X-ray diffraction imaging with high resolution…

The remote sensing of gases in complex mixtures at atmospheric pressure is a challenging problem and much attention has been paid to it. The most fundamental difference between this application and highly successful astrophysical and upper…

Chemical Physics · Physics 2016-11-18 Frank C. De Lucia , Douglas T. Petkie , Henry O. Everitt

We have developed a terahertz radiation detector that measures both the amplitude and polarization of the electric field as a function of time. The device is a three-contact photoconductive receiver designed so that two orthogonal…

Other Condensed Matter · Physics 2007-05-23 E. Castro-Camus , J. Lloyd-Hughes , M. B. Johnston , M. D. Fraser , H. H. Tan , C. Jagadish

We report here on terahertz (THz) digital holography on a biological specimen. A continuous-wave (CW) THz in-line holographic setup was built based on a 2.52 THz CO2 pumped THz laser and a pyroelectric array detector. We introduced novel…

Fraunhofer diffraction is a well-known phenomenon achieved with most wavelength even without lens. A single-shot intensity measurement of diffraction is generally considered inadequate to reconstruct the original light field, because the…

Image and Video Processing · Electrical Eng. & Systems 2019-12-04 An-Dong Xiong , Xiao-Peng Jin , Wen-Kai Yu , Qing Zhao

A superconducting microstrip half-wavelength resonator is proposed as a suitable band-pass filter for broadband moderate spectral resolution spectroscopy for terahertz (THz) astronomy. The proposed filter geometry has a free spectral range…

Instrumentation and Methods for Astrophysics · Physics 2021-09-23 Alejandro Pascual Laguna , Kenichi Karatsu , David J. Thoen , Vignesh Murugesan , Bruno T. Buijtendorp , Akira Endo , Jochem J. A. Baselmans

In this paper, the problem of terahertz pulsed imaging and reconstruction is addressed. It is assumed that an incomplete (subsampled) three dimensional THz data set has been acquired and the aim is to recover all missing samples. A…

Computer Vision and Pattern Recognition · Computer Science 2015-06-17 Vahid Abolghasemi , Hao Shen , Yaochun Shen , Lu Gan

We investigate the spatially and temporally resolved four-wave mixing of terahertz fields and optical pulses in large band-gap dielectrics, such as diamond. We show that it is possible to perform beam profiling and space-time resolved…