Beyond spectral homodyne detection: complete quantum measurement of spectral modes of light

TL;DR

This paper demonstrates that resonator detection enables complete quantum state reconstruction of spectral light modes, surpassing the limitations of spectral homodyne detection.

Contribution

The authors introduce and experimentally validate resonator detection as a superior method for full quantum measurement of spectral modes of light.

Findings

Resonator detection reveals quantum features missed by homodyne detection.

Experimental quantum state engineering shows differences detectable only with resonator detection.

Resonator detection achieves complete quantum state reconstruction.

Abstract

Spectral homodyne detection, a widely used technique for measuring quantum properties of light beams, cannot retrieve all the information needed to reconstruct the quantum state of spectral field modes. We show that full quantum state reconstruction can be achieved with the alternative measurement technique of resonator detection. We experimentally demonstrate this difference by engineering a quantum state with features that go undetected by homodyne detection but are clearly revealed by resonator detection.