Measuring the tuning curve of spontaneous parameter down-conversion using a comet-tail-like pattern

TL;DR

This paper investigates comet-tail-like interference patterns in spontaneous parametric down-conversion, providing a theoretical framework and simulations that match experimental observations, enabling parameter measurement of the SPDC process.

Contribution

It introduces a novel method to measure the tuning curve of SPDC using interference patterns caused by diffraction and angular spectrum effects.

Findings

Patterns are explained by interference and diffraction effects.

Simulation results align with experimental data.

The method allows for deducing SPDC parameters from observed patterns.

Abstract

The comet-tail-like interference patterns are observed using photons from the spontaneous parametric down-conversion (SPDC) process. The patterns are caused by the angular-spectrum-dependent interference and the diffraction of a blazed grating. We present the theoretical explanation and simulation results for these patterns, which are in good agreement with the experimental results. The most significant feature of the patterns is the bright parabolic contour profile, from which, one can deduce the parameter of the parabolic tuning curve of the SPDC process. This method could be helpful in designing experiments based on SPDC.