Absolute calibration of photodetectors: photocurrent multiplication versus photocurrent subtraction

TL;DR

This paper compares a new difference-signal calibration method for photodetectors using two-mode squeezed vacuum with traditional coincidence counting, demonstrating its effectiveness through quantum efficiency measurements.

Contribution

It introduces and tests a novel absolute calibration method based on difference-signal measurement, adapting it for counting detectors with dead-time effects.

Findings

The difference-signal method yields comparable quantum efficiency results to traditional methods.

The new method effectively accounts for dead-time effects in counting detectors.

Experimental validation confirms the method's accuracy and practicality.

Abstract

We report testing of the new absolute method of photodetectors calibration based on the difference-signal measurement for two-mode squeezed vacuum by comparison with the traditional absolute method based on the coincidence counting. Using low-gain parametric down conversion we have measured the quantum efficiency of a counting detector by both methods. The difference-signal method was adapted for the counting detectors by taking into account the dead-time effect.