Ruby laser repetitively pulsed at rates up to 500 kHz containing etalons and amplification

A multi-pulsed ruby laser system has been developed utilizing repetitive Q-switching technology. The laser system has applications in fields where high speed dynamic events are studied, e.g., ballistics and non-destructive test evaluation, using laser imaging diagnostics such as photography, holography, and various interferometric techniques. The laser system is capable of producing more than 50 pulses at a repetition rate in excess of 500 kHz with a nearly constant pulse-to-pulse energy of several mJ. The individual laser pulses are approximately 50 ns FWHM and the envelope of multiple pulses is greater than 200 microseconds. The method for multiple Q-switching by modulating the Pockels cell's quarter wave voltage and the formation of an individual Q- switched pulse have been investigated and a computational model has been formulated. The energy within the individual pulses formed in the oscillator cavity has been successfully increased without degradation of the temporal or pulse-to- pulse amplitude stability by propagating through an amplification section. Data of an amplified pulse train at a repetition rate of 500 kHz is given. Etalons for longitudinal mode selection and an iris for spatial mode selection have been incorporated for increased coherence and an image of a reconstructed hologram is presented.