Stationary transverse structures in solid-state degenerate-cavity lasers

M. Brunel, N. Barré, M. Romanelli, Institut de Physique de Rennes.

We describe longitudinally pumped solid-state lasers from both experimental and numerical points of view. We explore in detail the particular behaviors of non-degenerate as well as partially or fully degenerate cavities.

Our work provides some insight into the formation of high-order Ince-Gauss or Laguerre-Gauss modes. Namely we show analytically, numerically, and experimentally that it is impossible to excite IGnm modes (nm) with a Gaussian pump in non-degenerate cavities, contrary to a common belief. We also find the emergence of quasi-Ince and quasi-Laquerre Gaussian modes in the vicinity of degeneracy points, in full agreement with observations.

Numerical simulations are based on the Fox-Li algorithm. Experiments are conducted with diode-pumped Nd-doped lasers. We discuss extensions of this work towards the generation of original transverse modes.