Thermal effects of the quantum states generated from the isomorphs of PPKTP crystal

TL;DR

This study analyzes how temperature variations affect the spectral properties of biphotons generated from four isomorphs of PPKTP, revealing shifts in phase-matched wavelengths and implications for quantum information applications.

Contribution

It provides a theoretical and numerical investigation of temperature-dependent effects on biphoton properties from PPKTP isomorphs, highlighting shifts in spectral features.

Findings

Wavelength shifts with temperature for different isomorphs

Spectral purity remains unchanged despite temperature variations

HOM interference patterns are affected by thermal shifts

Abstract

We theoretically and numerically investigate the temperature-dependent properties of the biphotons generated from four isomorphs of periodically poled $\mathrm{KTiOPO_4}$ (PPKTP): i.e., PPRTP, PPKTA, PPRTA and PPCTA. It is discovered that the first type of group-velocity-matched (GVM) wavelength is decreased by 6.4, 1.2, 8.9, 25.6 and 6.3 nm, while the phase-matched wavelength is decreased by 4.4, -0.4, -1.2, 29.1 and 59.5 nm for PPKTP, PPRTP, PPKTA, PPRTA and PPCTA, respectively, when the temperature is increased from 20$\,^{\circ}\mathrm{C}$ to 120$\,^{\circ}\mathrm{C}$. Although the maximal spectral purity of the heralded single photons is not changed at different temperature, the Hong-Ou-Mandel (HOM) interference shows different patterns due to a shift of the joint spectral amplitude. These thermal effects are very important for precise control of the quantum state for the future applications in quantum information processing, for example, in quantum interference or spectroscopy.