Chirped quasi-phase-matching with Gauss sums for production of biphotons

TL;DR

This paper develops a detailed theoretical framework for biphoton generation via spontaneous parametric down-conversion in chirped quasi-phase-matched structures, using Gauss sums to analyze spectral properties.

Contribution

It introduces a novel approach modeling chirped quasi-phase-matching structures as layered assemblies and applies Gauss sums to describe biphoton spectra in detail.

Findings

Biphoton spectra show well-resolved spectral lines with few layers.

Broadband spectra form as the number of layers increases.

Chirping parameters significantly influence spectral properties.

Abstract

We study the theory of linearly chirped biphoton wave-packets produced in two basic quasi-phase-matching configurations: chirped photonic-like crystals and aperiodically poled crystals. The novelty is that these structures are considered as definite assembles of nonlinear layers that leads to detailed description of spontaneous parametric down-conversion (SPDC) processes through the discrete Gauss sums. We demonstrate that biphoton spectra for chirped photonic crystals involving a small number of layers consist from definite well-resolved spectral lines. We also discuss the forming of broadband spectra of signal (idler) waves in SPDC for both configurations as number of layers increases as well as in dependence of chirping parameters .