Detection Efficiency Characterization for Free-Space Single-Photon Detectors: Measurement Facility and Wavelength-Dependence Investigation

TL;DR

This paper introduces a new measurement setup for free-space single-photon detectors that accurately characterizes their wavelength-dependent efficiency, accounting for optical window transmissivity, thus improving detector calibration for quantum applications.

Contribution

The authors develop a novel experimental apparatus and methodology to measure wavelength-dependent detection efficiency, including optical window effects, enhancing accuracy over previous techniques.

Findings

Wavelength dependence of detector efficiency quantified

Optical window transmissivity effects characterized

Improved calibration method for single-photon detectors

Abstract

In this paper, we present a new experimental apparatus for the measurement of the detection efficiency of free-space single-photon detectors based on the substitution method. For the first time, we extend the analysis to account for the wavelength dependence introduced by the transmissivity of the optical window in front of the detector's active area. Our method involves measuring the detector's response at different wavelengths and comparing it to a calibrated reference detector. This allows us to accurately quantify the efficiency variations due to the optical window's transmissivity. The results provide a comprehensive understanding of the wavelength-dependent efficiency, which is crucial for optimizing the performance of single-photon detectors in various applications, including quantum communication and photonics research. This characterization technique offers a significant advancement in the precision and reliability of single-photon detection efficiency measurements.