Contactless method for studying temperature within the active element of a multidisk cryogenic amplifier

A new original method has been developed and experimentally implemented, allowing temperature fields to be contactlessly measured in the pump region of active elements in highpower-diode-pumped laser amplifiers, including those operating at cryogenic temperatures. The presence of a temperature gradient of ~57 K mm^-1 along the pump beam axis at the centre of the active element of the laser amplification unit operating at cryogenic temperatures with a pulse repetition rate up to 1 kHz is simulated and experimentally confirmed.