Instant single-photon Fock state tomography

TL;DR

This paper demonstrates a method for preparing and characterizing single-photon Fock states at high rates using pulsed homodyne tomography, enabling real-time system alignment and high-fidelity state measurement.

Contribution

It introduces a high-rate heralded single-photon source combined with real-time homodyne tomography for efficient quantum state characterization.

Findings

Single-photon states prepared at ~100 kHz rate.

Achieved a fidelity of approximately 57.6%.

Enabled on-the-fly alignment based on measurement data.

Abstract

Heralded single photons are prepared at a rate of ~100 kHz via conditional measurements on polarization-nondegenerate biphotons produced in a periodically poled KTP crystal. The single-photon Fock state is characterized using high frequency pulsed optical homodyne tomography with a fidelity of (57.6 +- 0.1)%. The state preparation and detection rates allowed us to perform on-the-fly alignment of the apparatus based on real-time analysis of the quadrature measurement statistics.