Amplitude and phase modulation of time-energy entangled two-photon states

TL;DR

This paper demonstrates experimental amplitude and phase modulation of time-energy entangled photon pairs, analyzing their wave functions and interference patterns using Fourier optics and a shaper-based interferometer.

Contribution

It introduces a novel method for combined amplitude and phase shaping of entangled photons and provides an analytic Fourier optical analysis of the setup.

Findings

Successful modulation of entangled photon wave functions

Analytic expression for the field distribution after shaping

Observation of two-photon interference effects

Abstract

We experimentally demonstrate amplitude and phase modulation of a time-energy entangled two-photon wave function. The entangled photons are produced by spontaneous parametric down-conversion, spectrally dispersed in an prism compressor, modulated in amplitude and/or phase, and detected in coincidence by sum-frequency generation. First, we present a Fourier optical analysis of the optical setup yielding an analytic expression for the resulting field distribution at the exit plane of the shaping apparatus. We then introduce amplitude and/or phase shaping and present results which can only be obtained through a combination of the two. Specifically, we use a shaper-based interferometer to measure the two-photon interference of an almost bandwidth-limited two-photon wave function.