In-situ heat input and high resolution thermal expansion sensing in a miniaturized side-pumped DPSS laser

Diode-pumped solid-state (DPSS) lasers are increasingly used in industrial high-power applications, including laser ignition. Optimizing such devices requires detailed knowledge of the underlying processes of laser beam creation. To monitor the dynamics of the lasing element's response to μs pump pulses, we developed a laser interferometric in-situ method capable of measuring the temperature rise in the laser rod, its expansion and the injected heat in real-time. These measurements lead to a better understanding of thermal lens effects and enable the development of improved, energy efficient cooling of the laser rods.