Parametric wave interaction in quadratic crystal with randomized distribution of ferroelectric domains

TL;DR

This paper investigates how randomized ferroelectric domain distributions in quadratic nonlinear crystals affect parametric wave interactions, including second and third harmonic generation, revealing the impact of disorder on efficiency and diffraction regimes.

Contribution

It provides analytical formulas for harmonic emission in disordered domains and analyzes the effects of randomness on different nonlinear diffraction regimes.

Findings

Randomness reduces efficiency in phase-matched harmonic generation.

Forward and Cerenkov frequency generation are insensitive to domain disorder.

Disorder causes angular spreading in harmonic emission.

Abstract

We study the parametric wave interaction in qua- dratic nonlinear media with randomized distribution of the ferroelectric domains. In particular, we discuss properties of second and cascaded third harmonic generation. We derive analytical formulas describing emission properties of the second and third harmonics in the presence of domain disorder and show that the latter process is governed by the characteristics of the constituent processes, i.e. second harmonic generation and sum frequency mixing. We demonstrate the role of randomness on various second and third harmonic generation regimes such as Raman-Nath and \v{C}erenkov nonlinear diffraction. We show that the randomness-induced incoherence in the wave interaction leads to deterioration of conversion efficiency and angular spreading of harmonic generated in the processes relying on transverse phase matching such as Raman-Nath. On the other hand forward and \v{C}erenkov frequency generation are basically insensitive to the domain randomness.