APDs as Single-Photon Detectors for Visible and Near-Infrared Wavelenghts down to Hz Rates

TL;DR

This paper evaluates the performance of avalanche photodiodes as single-photon detectors in the visible and near-infrared spectrum, demonstrating their effectiveness at very low light levels and specific wavelengths.

Contribution

It presents detailed measurements of APD performance at different wavelengths, including detection efficiency and dark count rates, for use in high-precision experiments.

Findings

Achieved a detection efficiency of 67% at 628 nm

Detected single photons at 1020 nm with 13% efficiency

Dark count rate of approximately 230 per second at specified settings

Abstract

For the SPECTRAP experiment at GSI, Germany, detectors with Single-Photon counting capability in the visible and near-infrared regime are required. For the wavelength region up to 1100 nm we investigate the performance of 2x2 mm^2 avalanche photo diodes (APDs) of type S0223 manufactured by Radiation Monitoring Devices. To minimize thermal noise, the APDs are cooled to approximately -170 deg. C using liquid nitrogen. By operating the diodes close to the breakdown voltage it is possible to achieve relative gains in excess of 2x10^4. Custom-made low noise preamplifiers are used to read out the devices. The measurements presented in this paper have been obtained at a relative gain of 2.2x10^4. At a discriminator threshold of 6 mV the resulting dark count rate is in the region of 230/s. With these settings the studied APDs are able to detect single photons at 628 nm wavelength with a photo detection efficiency of (67+-7)%. Measurements at 1020 nm wavelength have been performed using the attenuated output of a grating spectrograph with a light bulb as photon source. With this setup the photo detection efficiency at 1020 nm has been determined to be (13+-3)%, again at a threshold of 6 mV.