Comment on: Investigation of the thermal lens effect of the TGG crystal in high-power frequency-doubled laser with single frequency operation

TL;DR

This paper critically examines the claim that thermal lensing in TGG crystals causes step-like power behavior in high-power Nd:YVO4 lasers, proposing experimental methods to verify this hypothesis.

Contribution

It challenges previous assumptions by analyzing the thermal lens effect and suggests experimental approaches for direct evidence.

Findings

Questioned the validity of thermal lensing as the cause of observed behavior

Proposed experimental methods to directly verify thermal lens effects

Highlighted the need for direct evidence in thermal lens studies

Abstract

In their article, the authors of [Opt. Express 23, 4981 (2015)] observe step-like behavior and hysteresis of the output power of a diode-end-pumped Nd:YVO 4-laser as a function of pump power. While claiming that this behavior is a proof of thermal lensing in the intra-cavity TGG, no direct evidence is given. We will discuss here the validity of their statement, and propose an experimental proof.