Influence of the shape of a crystalline active element on the output power of a single-mode laser

An investigation was made of the influence of the shape of a YAG:Nd³⁺ active element on the power of the fundamental TEM₀₀ mode. It was found that if shallow grooves were formed in the active element between the crystallographic axes, at the places where the pumping induced the greatest birefringence, the output power increased by 40–50%. These grooves improved the removal of heat from the central part of the active element responsible for generating the TEM₀₀ mode and thus reduced the thermal deformation distorting the front of the light wave.