Small signal approximation method to determine output patterns of offaxis pumped solidstate lasers
Abstract
To determine the output patterns of offaxis pumped solidstate lasers, we develop a small signal approximation method to obtain the relative modal weightings of Hermite Gaussian modes. The advantage of the method is that the differential rate equations are simplified to linear algebraic equations, which can be easily solved. In order to prove the validity of the method, we experimentally demonstrated an offaxis pumped laser, and measured its relative modal weightings. The experimental results are in high concordance with the calculated results. Moreover, the characteristics of the modes near the threshold are investigated. The modes exhibit the competition effect at the beginning, and then the photon number of each mode turns into linear increasing with the pump power growing. Due to this linearity, we can calculate the relative modal weightings for an actual laser by the small signal method, although it always operates far above threshold.
 Publication:

Optics Communications
 Pub Date:
 January 2021
 DOI:
 10.1016/j.optcom.2020.126406
 Bibcode:
 2021OptCo.47826406L
 Keywords:

 Solidstate laser;
 Hermite Gaussian mode;
 Small signal method