LASER-PULSE STRETCHING VIA ENHANCED CLOSED-LOOP CONTROL WITH SLOW Q-SWITCHING

A pulse stretching technique in a Q-switched ruby laser oscillator is described. The major improvement to our previously developed pulse stretching circuit consists in a more adequate waveform for the feedforward part. This new system gives fairly flat pulses with adjustable duration up to ∼ 100 μs and good coherence length in excess of 11 m. The cavity is followed by several amplifiers and produces light energies up to 8 J for holographic recording of particle tracks in the Fermilab 15-foot bubble chamber. The considerably increased coherence length will find applications in many fields of pulsed holography and its use with fiber optics is particularily promising. © 1990.