  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.
