Far-infrared spectroscopy can reveal secrets of galaxy evolution and heavy-element enrichment throughout cosmic time, and astronomers worldwide are designing cryogenic space telescopes for far-IR spectroscopy. The most challenging aspect is a far-IR detector which is both exquisitely sensitive (limited by the zodiacal-light noise in a narrow band (lambda/delta lambda ~1000)) and array able to tens of thousands of pixels. The quantum capacitance detector (QCD) being developed at MDL, is a 50mK device adapted from quantum computing applications in which photon-produced free electrons in a superconductor tunnel into a small capacitive island embedded in a resonant circuit. The QCD has optically-measured noise equivalent power (NEP) of 2x10-20 W Hz-1/2 at 1.5THz under 10-19W of optical loading, making it the most sensitive far-IR detector ever demonstrated. The QCD has further demonstrated individual far-IR photon counting, confirming the exquisite sensitivity and suitability for cryogenic space astrophysics. In this lecture, the development of the Quantum Capacitance detector will be highlighted, from inception through proof of concept devices, culminating with the demonstration of single photon detection. Current development efforts will be discussed.
- Particle Physics
- Scientific Series