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In this paper, an overview of main results concerning THz detection by nanometer field effect transistors (FETs) and heterojunction based transistors (HBTs) is presented. Different GaInAs/InP and GaN/AlGaN nanometer field effect transistors based detectors are presented. We present also first Silicon C-MOS transistors based integrated circuits for wireless communication in sub-THz range. Special attention...
We present the low frequency noise and the photoresponse in InP double heterojunction bipolar transistor (DHBT) THz detectors. A current responsivity of 0.23 A/W and a noise equivalent power of 4·10−10 W/Hz1/2 have been measured at 1 kHz modulation frequency. The collector bias can substantially reduce the noise equivalent power.
Recent developments of THz detector arrays based on plasma wave field effect transistors are presented. By simultaneous development of the transistor arrays with their read-out circuits and diffractive 3D printed optics we demonstrate systems for imaging in 300 GHz atmospheric window with cameras or fast linear scanner. The first high speed THz postal scanner developed for real time fast A4 envelopes...
Fabrication and experimental tests of materials and optics for Terahertz range used in field effect transistor detectors arrays are described. The method using diffractive optics, fabricated in 3D printing technology, was used for tests with GaN/AlGaN based FETs sub-THz detectors working in 300 GHz atmospheric window. The lens arrays focus energy exactly on the detectors and additionally reduce mutual...
An overview of main results concerning THz detection related to plasma nonlinearities in nanometer field effect transistors is presented. In particular nonlinearity and dynamic range of these detectors are discussed. As a conclusion, we will show one of the first real world application of the FET THz detectors: a demonstrator of the imager developed for fast postal security.
Experimental and theoretical investigations of the influence of substrate thickness on the performance of Si field effect transistor terahertz detectors are presented‥ We show that in the case of planar metal antennas a significant portion of incoming radiation, instead of being coupled to the transistors, may be coupled to the substrate leading to important responsivity losses‥ The ways of avoiding...
We report on room-temperature detection of sub-terahertz radiation by InP double heterojunction bipolar transistors designed for 100 Gbit/s circuit applications. Maximum responsivity of 250 V/W around 272 GHz were achieved at room-temperature under unbiased base-emitter and base-collector conditions. We show also that these detectors can operate as sensitive broadband THz detectors in THz imaging...
We demonstrate detection of individual pulses of terahertz radiation generated in femtosecond laser systems by InGaAs plasma-wave terahertz detectors. Nonlinearity of the detection mechanism is analyzed experimentally by comparison of saturation effects at femtosecond and nanosecond terahertz excitations. Good sensitivity and wide dynamic range make these detectors promising for short-pulsed terahertz...
We report on room-temperature plasmonic detection of the thermal emission from a black body in the terahertz and mid-infrared domains by dual-grating-gate InAlAs/InGaAs/InP high electron mobility transistors (HEMTs). In such detectors, the asymmetric grating gate of a large area acts as an effective antenna that improves the performance in the two spectral domains.
Two-dimensional electron plasma in nanometer size field effect transistors can oscillate in Terahertz (THz) frequencies, far beyond transistors fundamental cut-of frequencies. We propose an overview of some important and recent results concerning THz detection by nanometer field effect transistors. The subjects were selected in a way to stress some new aspects of the physics of nanometer scale field...
The goal of our work was to study the capability of field effect transistors to measure high power THz radiation at frequencies from 0.1 up to 3 THz and to determine the linear detection limits. We observed different types of the photoresponse dependence on the incident radiation power. We qualitatively explain the unusual sub-linear behavior observed in high intensities.
Transistors are possible THz detectors using rectification in the channel that can be applied for detection of high data-rate wireless communications, based on THz-frequency carrier. For the first time, we present the transmission of pseudo-random bit sequence at 0.2 THz using a commercial GaAs transistor and demonstrate open eye patterns up to 0.250 Gbps.
Antenna-coupled field effect transistors have been developed as plasma-wave THz detectors in both InAs nanowire and graphene channel materials. Room temperature operation has been achieved up to 3 THz, with noise equivalent power levels < 10−10 W/Hz1/2, and high-speed response already suitable for large area THz imaging applications.
We report on terahertz wireless communication experiments at 0.2 THz, using a commercial GaAs field-effect-transistor as detector. For the first time, we will present the transmission of pseudo-random bit sequence at 0.2 THz using this commercial transistor and demonstrate open eye-patterns up to 1.5 Gbps. This transistor is integrated into a machined horn, so that its sensitivity is improved to 1...
We report on Terahertz wireless communications and fast imaging experiments at 300 GHz, using nanometer-sized transistors as detectors. The physical mechanism of the detection is related to the overdamped plasma waves in the transistor channel.
Test chips with Si MOSFETs integrating bow tie antennas are investigated to check the polarization and frequency dependence of THz sensitivity. The azimuthal angle corresponding to the maximum sensitivity changes with the pixel position on the chip. This means that the surrounding pixels affect the bow tie radiation pattern and possibly contribute to the antenna coupling. The frequency dependence...
The paper demonstrates a complete acquisition chain of a 300GHz to 1THz image sensor with on-chip multiplexing in a 0.13μm bulk silicon CMOS technology. The pixel consumes less than 100μW and has a responsivity of 90kV/W at 300GHz and of 1.8kV/W at 1.05THz respectively. High resolution and contrast THz images revealing the inner structure of tree leaves are presented. These results show that multi-frequency...
We present our results concerning THz detection and imaging by silicon FETs. We show that FETs are sensitive and fast enough to be used to construct focal plane arrays of future THz cameras.
We present the experimental study of the direct emission - detection system based on the THz Quantum Cascade Laser as a source and Hot Electron Bolometer (HEB) detector - in view of its application as an optical communication system. We show that the system can efficiently transmit the QCL Terahertz pulses. We estimate the maximal modulation speed of the system to be about several GHz and show that...
We evaluate the optical performance of AlGaN/GaN MISFETs as a non-resonant sub-terahertz, room temperature detector. The single-pixel responsivity and the noise equivalent power are determined. The efficiency of the detection is demonstrated by the room temperature imaging of different solutions of acetone in cyclohexane.
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