Room temperature mid-IR single photon spectral imaging

TL;DR

This paper introduces a novel room-temperature mid-IR spectral imaging system using upconversion, achieving high sensitivity, low noise, and high spatial resolution, advancing mid-IR detection technology for scientific and medical applications.

Contribution

A new field-deployable upconversion system for sensitive, high-resolution mid-IR spectral imaging at room temperature, surpassing cryogenic detector noise levels.

Findings

Dark noise of 0.2 photons/spatial element/second at room temperature

Single photon imaging with 200 x 100 spatial resolution

Quantum efficiency of about 20% at 3 μm

Abstract

Spectral imaging and detection of mid-infrared (mid-IR) wavelengths are emerging as an enabling technology of great technical and scientific interest; primarily because important chemical compounds display unique and strong mid-IR spectral fingerprints revealing valuable chemical information. While modern Quantum cascade lasers have evolved as ideal coherent mid-IR excitation sources, simple, low noise, room temperature detectors and imaging systems still lag behind. We address this need presenting a novel, field-deployable, upconversion system for sensitive, 2-D, mid-IR spectral imaging. Measured room temperature dark noise is 0.2 photons/spatial element/second, which is a billion times below the dark noise level of cryogenically cooled InSb cameras. Single photon imaging and up to 200 x 100 spatial elements resolution is obtained reaching record high continuous wave quantum efficiency of about 20 % for polarized incoherent light at 3 \mum. The proposed method is relevant for existing and new mid-IR applications like gas analysis and medical diagnostics.