The Ultra Sensitive Silicon Sensor1 is an all silicon bolometer that utilizing active thermal isolation to overcome
limitations in conventional bolometers. Inherently, bolometers are slower and less sensitive than quantum detectors.
However, because of low cost and room temperature operation, bolometers are being used in many cameras. IC
technology used for producing staring focal planes has ameliorated the bolometer's slow speed and lower sensitivity
issues. Better thermal isolation and thermal responsivity materials have yielded significant sensitivity improvements.
Currently, LWIR bolometer's sensitivity is about 10X below the theoretical limit. Achieving theoretical sensitivity will
greatly increase the application sphere of bolometer cameras. Theoretically, performance improvements are possible
with better thermal isolation, better thermal responsivity, and a faster time constant. Examining these limitations has
allowed us to formulate solutions to these problems and open the opportunity for application of bolometers to MMwave
imaging. Large (10X) sensitivity improvements are possible by replacing passive thermal isolation with active
thermal isolation. Active thermal isolation utilizes electro-thermal feedback to greatly improve thermal isolation and
this leads directly to corresponding responsivity improvements. Improved thermal isolation does increase the thermal
time constant, however, this increase is offset by using microantennas and/or microlenses. A detail analysis is presented
on the theoretical operation of the all silicon USSS bolometer.
The discovery of high-temperature superconductors (HTS) spawned many potential applications, including optical detectors. Realizing viable superconducting detectors requires achieving performance superior to competing and more mature semiconductor detector technologies, and quantum detector technologies in particular. We review why quantum detectors are inherently more sensitive than thermal or bolometric detectors. This sensitivity advantage suggests that for operation at cryogenic temperatures, we should be developing only quantum superconducting detectors. Accordingly, we introduce and describe the structure and the operation of a superconducting quantum detector with a superconducting quantum interference device (SQUID) readout circuit. The superconducting quantum detector, consisting of a superconducting loop, produces a photosignal in response to photoinduced changes in the superconducting condensate's kinetic inductance. The superconducting quantum detector is designed to operate only in the superconducting state and not in the resistive or transition states.
The discovery of high temperature superconductors (HTS) spawned many potential applications, including optical detectors. Realizing viable superconducting detectors requires achieving performance superior to competing and more mature semiconductor detector technologies, and quantum detector technologies in particular. We review why quantum detectors are inherently more sensitive than thermal or bolometric detectors. This sensitivity advantage suggests that for operation at cryogenic temperatures we should be developing only quantum superconducting detectors. Accordingly, we introduce and describe the structure and the operation of a superconducting quantum detector with a SQUID read-out circuit. The superconducting quantum detector, consisting of a superconducting loop, produces a photosignal in response to photoinduced changes in the condensate's kinetic inductance. The superconducting quantum detector is designed to operate only in the superconducting state and not in the resistive or transition states.
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