http://arxiv.org/abs/1406.4010
We demonstrate photon-noise limited performance at sub-millimeter wavelengths in feedhorn-coupled, microwave kinetic inductance detectors (MKIDs) made of a TiN/Ti/TiN trilayer superconducting film, tuned to have a transition temperature of 1.4 K. The lumped-element detector design enables dual-polarization sensitivity. The devices are fabricated on a silicon-on-insulator (SOI) wafer. Micro-machining of the SOI wafer backside creates a quarter-wavelength backshort optimized for efficient coupling at 250 $\mu$m. Using frequency read out and when viewing a variable temperature thermal source, we measure device noise consistent with photon noise when the incident optical power is $>$1 pW, corresponding to noise equivalent powers $>$ 4$\times 10^{-17}$ W/$\sqrt{\mathrm{Hz}}$. This sensitivity makes these devices suitable for broadband photometric applications at these wavelengths.
J. Hubmayr, J. Beall, D. Becker, et. al.
Tue, 17 Jun 14
10/63
Comments: submitted to APL