Patent ID: 8179929

Claim:
A method for generating high peak power narrow spectrum optical radiation, comprising: exciting a master oscillator so as to lase a narrowband seed radiation having a single longitudinal master mode; providing a slave oscillator operative to generate a broadband slave radiation having a plurality of longitudinal side slave modes and a dominant slave mode; and injecting the single longitudinal master mode into the dominant slave mode so that the dominant slave mode increases while suppressing the side slave modes, thereby providing the slave radiation with a narrowed spectra in which a side mode suppression ratio (SMSR) between the dominant and side slave modes exceeds 40 dB; determining the SMSR at the output of the slave oscillator and comparing the determined SMSR to a SMSR reference value; and controlling a length of a resonant cavity of the slave oscillator by changing a temperature therein if the determined and reference SMSR are substantially different.