Noise equivalent power of a NbTiN-Al-based kinetic inductance detector for terahertz sensing

Abstract We have designed and fabricated a superconducting hybrid NbTiN-Al kinetic inductance detector (KID) over a broad band centered at 4.3 THz. The detector sensitivity is characterized by changing the bath temperature in a dark environment. Both amplitude and phase readouts are performed. The measured electrical noise equivalent power for phase readout is about 2.6 × 10 −18 W · Hz −0.5 at 200 mK. This ultra-sensitive KID, which enables large arrays with frequency domain multiplexing, is promising for imaging instruments in space-based far-infrared observatories.