645 research outputs found
CMOS Terahertz Metamaterial Based 64 × 64 Bolometric Detector Arrays
We present two terahertz detectors composed of microbolometer sensors (vanadium oxide and silicon pn diode) and metamaterial absorbers monolithically integrated into a complementary metal oxide semiconductor (CMOS) process. The metamaterial absorbers were created using the metal-dielectric-metal layers of a commercial CMOS technology resulting in low-cost terahertz detectors. The scalability of this technology was used to form a 64 × 64 pixel terahertz focal plane array
Detection of incoherent broadband terahertz light using antenna-coupled high-electron-mobility field-effect transistors
The sensitivity of direct terahertz detectors based on self-mixing of
terahertz electromagnetic wave in field-effect transistors is being improved
with noise-equivalent power close to that of Schottky-barrier-diode detectors.
Here we report such detectors based on AlGaN/GaN two-dimensional electron gas
at 77~K are able to sense broadband and incoherent terahertz radiation. The
measured photocurrent as a function of the gate voltage agrees well with the
self-mixing model and the spectral response is mainly determined by the
antenna. A Fourier-transform spectrometer equipped with detectors designed for
340, 650 and 900~GHz bands allows for terahertz spectroscopy in a frequency
range from 0.1 to 2.0~THz. The 900~GHz detector at 77~K offers an optical
sensitivity about being comparable to a commercial
silicon bolometer at 4.2~K. By further improving the sensitivity,
room-temperature detectors would find applications in active/passive terahertz
imaging and terahertz spectroscopy.Comment: 4.5 pages, 5 figure
High performance bilayer-graphene Terahertz detectors
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
and a noise equivalent power in the 0.29-0.38 THz range, in photovoltage and photocurrent mode.
The potential of this technology for scalability to higher frequencies and the
development of flexible devices makes our approach competitive for a future
generation of THz detection systems.Comment: 8 pages, 5 figures. Submitted to Applied Physics Letter
MEMS-Based Terahertz Detectors
A MEMS based novel THz detector structure is designed and realized by micro fabrication. The detector is then characterized to extract its mechanical performance. Operating in 1-5 THz band, the detector has a pixel size of 200 μm × 200 μm. Bimaterial suspension legs consist of Parylene-C and titanium, the pair of which provides a high mismatch in coefficients of thermal expansion. The pixel is a suspended Parylene-C structure having a 200 nm-thick titanium metallization. Operation principle relies on conversion of absorbed THz radiation into heat energy on the pixel. This increases the temperature of the free-standing microstructure that is thermally isolated from the substrate. The increase in temperature induces mechanical deflection due to bimaterial springs. The detector is designed to deliver a noise equivalent temperature difference (NETD) less than 500 mK and a refresh rate of 30 Hz
Sequential multi-photon strategy for semiconductor-based terahertz detectors
A semiconductor-based terahertz-detector strategy, exploiting a
bound-to-bound-to-continuum architecture, is presented and investigated. In
particular, a ladder of equidistant energy levels is employed, whose step is
tuned to the desired detection frequency and allows for sequential multi-photon
absorption. Our theoretical analysis demonstrates that the proposed
multi-subband scheme could represent a promising alternative to conventional
quantum-well infrared photodetectors in the terahertz spectral region.Comment: Submitted to Journal of Applied Physic
A monolithic resonant terahertz sensor element comprising a metamaterial absorber and micro-bolometer
In this article a monolithic resonant terahertz sensor element with a noise equivalent power superior to that of typical commercial room temperature single pixel terahertz detectors and capable of close to real time read-out rates is presented. The detector is constructed via the integration of a metamaterial absorber and a micro-bolometer sensor. An absorption magnitude of 57% at 2.5 THz, a minimum NEP of inline image and a thermal time constant of 68 ms for the sensor are measured. As a demonstration of detector capability, it is employed in a practical Nipkow terahertz imaging system. The monolithic resonant terahertz detector is readily scaled to focal plane array formats by adding standard read-out and addressing circuitry enabling compact, low-cost terahertz imaging
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