Quantum interrogation of imperfect absorbers using post-selection

TL;DR

This paper introduces a quantum interrogation method using post-selection and interference to detect imperfect absorbers efficiently, robustly, and with the ability to quantify transmittance, applicable to single-photon and attenuated sources.

Contribution

It presents a novel quantum interrogation scheme leveraging post-selection for high-efficiency detection of imperfect absorbers, including noise robustness and transmittance quantification.

Findings

Achieves high-efficiency detection with single-pass measurement.

Demonstrates robustness against noise through post-selection.

Provides a method to quantify transmittance via fringe visibility.

Abstract

We propose a scheme for quantum interrogation measurements using constructive interference and post-selection to achieve single-pass high-efficiency detection for imperfect absorbers. We illustrate that our method works for heralded single-photon and weak attenuated sources. We also study the influence of noise in our experimental implementation and show that post-selection imparts additional robustness to the scheme against noise. We further demonstrate that fringe visibility from post-selection interferometry can be used to quantify the transmittance of the imperfect absorber. An interesting link between the interrogation and weak values of nonunitary operators is also highlighted.