The non-equilibrium response of a superconductor to pair-breaking radiation measured over a broad frequency band

We have measured the absorption of terahertz radiation in a BCS superconductor over a broad range of frequencies from 200 GHz to 1.1 THz, using a broadband antenna-lens system and a tantalum microwave resonator. From low frequencies, the response of the resonator rises rapidly to a maximum at the gap edge of the superconductor. From there on,...

Evidence of a Nonequilibrium Distribution of Quasiparticles in the Microwave Response of a Superconducting Aluminum Resonator

In a superconductor, absorption of photons with an energy below the superconducting gap leads to redistribution of quasiparticles over energy and thus induces a strong nonequilibrium quasiparticle energy distribution. We have measured the electrodynamic response, quality factor, and resonant frequency of a superconducting aluminium microwave...

HARP: A submillimetre heterodyne array receiver operating on the James Clerk Maxwell Telescope

This paper describes the key design features and performance of HARP, an innovative heterodyne focal-plane array receiver designed and built to operate in the submillimetre on the James Clerk Maxwell Telescope (JCMT) in Hawaii. The 4x4 element array uses SIS detectors, and is the first sub-millimetre spectral imaging system on the JCMT. HARP...