Energy-resolved detection of single infrared photons with {\lambda} = 8 {\mu}m using a superconducting microbolometer

TL;DR

This paper demonstrates the detection of single 8 μm infrared photons using a superconducting titanium microbolometer with high energy resolution, enabling potential applications in infrared photon spectroscopy.

Contribution

It introduces a titanium transition-edge sensor microbolometer capable of resolving single infrared photons with unprecedented energy resolution.

Findings

Successful detection of single 8 μm photons

Poisson photon counting including 3-photon events

Achieved energy resolution of 0.11 eV, 70% of photon energy

Abstract

We report on the detection of single photons with {\lambda} = 8 {\mu}m using a superconducting hot-electron microbolometer. The sensing element is a titanium transition-edge sensor with a volume ~ 0.1 {\mu}m^3 fabricated on a silicon substrate. Poisson photon counting statistics including simultaneous detection of 3 photons was observed. The width of the photon-number peaks was 0.11 eV, 70% of the photon energy, at 50-100 mK. This achieved energy resolution is one of the best figures reported so far for superconducting devices. Such devices can be suitable for single photon calorimetric spectroscopy throughout the mid-infrared and even the far-infrared.