Terahertz electro-optic Kerr effect in LaAlO3

TL;DR

This study explores the terahertz electro-optic Kerr effect in LaAlO3, revealing how material anisotropy and interference effects influence the Kerr response, which is crucial for interpreting ultrafast measurements in THz experiments.

Contribution

It demonstrates the frequency-dependent Kerr effect dynamics in LaAlO3, highlighting the role of anisotropy and interference in shaping the response, which was not previously characterized.

Findings

Kerr effect dynamics depend on material anisotropy.

Interference causes quasi-phase matching conditions.

Kerr response varies with THz frequency, showing uni- and bipolar shapes.

Abstract

In this letter, we investigate the terahertz (THz) electro-optic Kerr effect (KE) dynamics in LaAlO3 (LAO), a widely used substrate for thin film preparation. We show that the KE dynamics strongly depend on the material anisotropy due to interference between THz field-induced and strain-induced optical birefringence. Such interference leads to quasi-phase matching conditions of the KE, which becomes strongly frequency dependent. Depending on the THz frequency, the KE exhibits a uni- and bipolar shape of the quadratic response. The demonstrated effects will be present in a wide variety of materials used as substrates in different THz-pump laser-probe experiments and need to be considered in order to disentangle the different contributions to the measured ultrafast dynamic signals.