Tomography of Spatial Mode Detectors

TL;DR

This paper introduces a new method inspired by quantum detector tomography to analyze and calibrate spatial mode detectors using only Gaussian beams, improving the accuracy of mode measurement in quantum optics.

Contribution

It presents a novel calibration technique for holographic spatial mode detectors based on quantum detector tomography principles, enabling full statistical reconstruction of their POVM elements.

Findings

Calibrated spatial mode detectors with improved accuracy.

Full statistical reconstruction of POVM elements.

Demonstrated effectiveness using experimental Gaussian beams.

Abstract

Transformation and detection of photons in higher-order spatial modes usually requires complicated holographic techniques. Detectors based on spatial holograms suffer from non-idealities and should be carefully calibrated. We report a novel method for analyzing the quality of projective measurements in spatial mode basis inspired by quantum detector tomography. It allows us to calibrate the detector response using only gaussian beams. We experimentally investigate the inherent inaccuracy of the existing methods of mode transformation and provide a full statistical reconstruction of the POVM (positive operator valued measure) elements for holographic spatial mode detectors.