Optical NEP in Hot-Electron Nanobolometers

TL;DR

This paper reports the first measurement of optical NEP in titanium superconducting hot-electron nanobolometers, achieving record low NEP suitable for space telescope applications.

Contribution

First measurement of optical NEP in Ti superconducting nano-HEBs, demonstrating record sensitivity at cryogenic temperatures.

Findings

Achieved NEP of 3x10^{-19} W/Hz^{1/2} at 50 mK

Demonstrated suitability for space telescope instruments

Discussed potential improvements for detector sensitivity

Abstract

For the first time, we have measured the optical noise equivalent power (NEP) in titanium (Ti) superconducting hot-electron nanobolometers (nano-HEBs). The bolometers were 2{\mu}mx1{\mu}mx20nm and 1{\mu}mx1{\mu}mx20nm planar antenna-coupled devices. The measurements were done at {\lambda} = 460 {\mu}m using a cryogenic black body radiation source delivering optical power from a fraction of a femtowatt to a few 100s of femtowatts. A record low NEP = 3x10^{-19} W/Hz^{1/2} at 50 mK has been achieved. This sensitivity meets the requirements for SAFARI instrument on the SPICA telescope. The ways for further improvement of the nano-HEB detector sensitivity are discussed.