External quantum efficiency enhancement by photon recycling with backscatter evasion

TL;DR

This paper demonstrates that recycling reflected photons can enhance the external quantum efficiency of photodiodes without increasing backscatter, improving signal quality in quantum optical experiments.

Contribution

The study introduces a photon recycling method with backscatter evasion to boost photodiode quantum efficiency, a novel approach in quantum optics.

Findings

External QE increased by 0.01-0.06 in InGaAs PDs.

QE enhancement observed over a wide range of incident angles.

Backscatter was not increased by the recycling technique.

Abstract

The nonunity quantum efficiency (QE) in photodiodes (PD) causes deterioration of signal quality in quantum optical experiments due to photocurrent loss as well as the introduction of vacuum fluctuations into the measurement. In this paper, we report that the external QE enhancement of a PD was demonstrated by recycling the reflected photons. The external QE for an InGaAs PD was increased by 0.01 - 0.06 from 0.86 - 0.92 over a wide range of incident angles. Moreover, we confirmed that this technique does not increase backscattered light when the recycled beam is properly misaligned.