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Bow-tie antenna coupled field-effect transistors have been implemented in 0.25 μm AlGaN/GaN process technology and have been mounted on an aplanatic hemispherical silicon substrate lens. By asymmetric coupling of 590-GHz radiation to the channel, the transistors are used as direct power detectors, achieving system noise-equivalent power values of 166 pW/√Hz at 590 GHz (referred to the total beam power)...
The realization of large format fully sampled sensitive focal plane arrays of direct detectors is a long standing development goal for advanced astrophysical instrumentation for submillimeter wavelengths. Recently a superconducting microwave kinetic inductors detector (MKID) technology has been developed which offers high sensitivity and unprecedented multiplexing ratio. We report on development of...
X-Spec is a moderate-resolution (R=400–700), multi-beam survey spectrometer covering the 190–520 GHz band under development for CCAT. It will employ a superconducting lithographically-patterned on-chip spectrometer technology, called SuperSpec. The spectrometer employs a filterbank architecture, and consists of a series of half-wave resonators formed by lithographically-patterned superconducting transmission...
Utilizing state-of-the-art TES detector arrays, the SAFARI imaging spectrometer onboard the Japanese SPICA mission will take maximum advantage of a deeply cooled 3m class space telescope, offering the far-infrared astronomical community unprecedented sensitivity, and mapping efficiency, in the 34–210 μm wavelength range filling the gap between JWST and ALMA.
We discuss measurement system and method for establishing traceability of terahertz (THz) power to NIST standards over a 0.3 to 7.5 THz range. In addition, we describe the performance of an electrically-calibrated thermopile detector, which is used as the NIST standard for THz power measurements. Specifically, we present measurements of the reflectance and spatial uniformity of the thermopile detector.
We report our recent work to improve a number of performance attributes of “KIDcam,” a passive THz imaging camera based on frequency multiplexed Lumped Element Kinetic Inductance Detectors (LEKIDs.) The array operates at 250mK but the entire instrument is liquid cryogen-free and can be operated remotely and automatically. It offers high sensitivity throughout the THz region with video rate frame capture...
Properties of antenna-coupled microbolometers optimized for room temperature 300 GHz and 600 GHz resonant frequency detection is reported. Dipole antenna placed on freestanding SiN membrane is used to couple THz radiation power to the titanium-based thermo-resistor. We demonstrate that antenna-coupled micro-bolometers can be well suited for beam profile imaging of the THz pulses emitted by the photoconductive...
We discuss some recent astronomical results from the Herschel Space Observatory, and indicate future directions for astronomy and astrophysics enabled by submillimeter/far-infrared observations. A huge amount remains to be done, but it will require improved ground-based, suborbital, and space facilities. New technology enabling large format detectors of different types is also needed. Efforts underway...
X-Spec is a multi-beam, R=400–700 survey spectrometer covering 190–520 GHz under development for CCAT. It measure the bright atomic fine-structure and molecular rotational transitions that cool galaxies' interstellar gas, in particular, the 158 μm rest-frame [CII] transition which is accessible from z=9.5 to z=3.5, With the wide bandwidth and multi-object capability, X-Spec/CCAT will be more powerful...
We have developed a calorimeter for a metrology standard for measuring the power of terahertz (THz) waves. Since the THz calorimeter is based on the thermal balance between heat produced by THz waves and direct current (DC), it requires an equivalent factor for converting from THz to DC power. The DC equivalent factor, which is defined as the ratio between the thermal efficiency of THz and DC powers,...
The frequency characteristics of commercially available pyro-electric detectors have been compared in the range from 0.9 to 2.8 THz by using an intense continuously-tunable terahertz (THz)-wave source. We have found that the THz-wave interference inside the detector has considerable effect on the performance.
To evaluate terahertz emission from intrinsic Josephson junctions, we used a YBa2Cu3O7−δ (YBCO) grain boundary Josephson junction as a terahertz detector. Shapiro steps have been clearly seen on the current-voltage curves of the YBCO junction irradiated with the emission from either a VDI-Tx-S140 transmitter (tens of μW at 620 GHz) or a Bi2Sr2CaCu2O8−x stack (25 μW at 500 GHz). While the harmonic...
A terahertz detector using an InAlAs/InGaAs high-electron-mobility-transistor (HEMT) integrated with a bow-tie antenna was proposed and fabricated. By utilizing ballistic transport in the short-channel, a current sensitivity of 1.5 A/W at 280 GHz was achieved by the detector having 70-nm T-gate HEMT without applying drain bias. We also measured the drain bias dependence of current sensitivity on the...
Approaches based on thinning down the substrate under the antenna are often used in order to increase efficiency of detectors built with MOSFETs and antennae printed on thick substrates. Such detectors have relatively low responsivity. In applications where cheap individual pixels are required, standard silicon lenses used to increase the responsivity are prohibitively expensive. In this paper an...
We report on the development of a tunable antenna coupled intersubband terahertz (TACIT) detector based on GaAs/AlGaAs two dimensional electron gas. A successful device design and micro-fabrication process have been developed which maintain the high mobility (1.1×106 cm2/V-s at 10K) of a 2DEG channel in the presence of a highly conducting backgate. Gate voltage-controlled device resistance and direct...
High quality Mn-Co-Ni-O (MCN) spinel films are prepared on Al2O3 substrate by RF magnetron sputtering (RF) and chemical solution deposition (CSD). The microstructural characterizations reveal the films present excellent crystallization and compact surface. The variable temperature electrical results show the films have temperature coefficient of resistance (TCR) of −3.8 %/K at 295 K. Based on the...
A FET detector, fabricated in a standard CMOS technology and coupled to a bow-tie antenna is characterized in terms of spatial response by using a deconvolution method. An optical setup is used to produce a predictable impulse response. The resulting spatial response shows interaction with other structures present on the chip, while the measured shape is in agreement with the antenna effective area...
We developed a THz imaging system based on a broadband thermal source (at 500 °C) and an asymmetric semiconductor nanochannel, the self-switching nanodiode (SSD), as a room-temperature detector. The maximum resolution was better than 0.5 mm full width at half maximum. The radiation was coupled to the SSD through a microantenna, whose geometry determined the frequency bandwidth of the system. While...
We present Terahertz imaging with a 1D multichannel time-domain spectroscopy system (TDS) which operates with a photoconductive array of 15 detection channels excited by a 1030 nm femtosecond fiber laser. The emitter and detector are photoconductive antennas based on InGaAs/InAlAs multi-layer heterostructures (MLHS). The simultaneous measurement of 15 THz pulses with a pixel pitch of 1 mm increases...
This paper presents a measurement-based analysis of operation of an example MOSFET detector integrated with a narrow-band patch antenna. First, responsivity of the detector was measured versus frequency of incident wave revealing two responsivity peaks, and then the antenna and the transistor were on-wafer probed to extract their impedances and antenna resonances in order to better explain the behavior...
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