Basis- and Channel-Selective Quantum Photodetection

TL;DR

This paper introduces a generalized quantum photodetection framework that incorporates electric and magnetic field contributions, enabling basis- and channel-selective detection in engineered quantum optical systems.

Contribution

It develops a new theoretical model for quantum photodetection that accounts for electric and magnetic field effects, extending beyond traditional electric-field-only responses.

Findings

Complete detector-amplitude cancellation in far-field reference case

Detector rotation of measurement basis in single-photon models

Achieving unit absorption at critical coupling in resonant detectors

Abstract

Photodetection converts optical quantum states into measurement events, but the usual electric-field response model becomes restrictive when the detector response is shaped by cavity, superconducting, or metamaterial engineering. We develop a generalized quantum photodetection framework in which electric and magnetic field amplitudes contribute coherently to the detection operator, and analyze it in a far-field two-source geometry, a two-mode single-photon setting, and a lossy resonant detector model. The far-field reference case exhibits complete detector-amplitude cancellation, absent in the electric-only Glauber response, while the single-photon model shows that the detector continuously rotates the effective measurement basis and controls the first-order visibility via an exact closed-form law. In the resonant realization, a monitored radiative output channel can be dark while the detector remains internally excited and absorptive, with unit absorption of the matched input mode at critical coupling. These results identify basis-selective readout and channel-selective absorption as experimentally relevant signatures of engineered electric-magnetic photodetection.