Reduction of timing jitter in a Q-Switched Nd:YAG laser by direct bleaching of a Cr4+:YAG saturable absorber

Abstract

A method for optical triggering of a Q-switched Nd:YAG laser by direct bleaching of a Cr:YAG saturable absorber is described. This method involves the bleaching of a thin sheet of the saturable absorber from a direction orthogonal to the lasing axis using a single laser diode bar, where the Cr:YAG transmission increased from a non-bleached value of 47% to a bleached value of 63%. For steady state operation of a passively Q-switched laser (PRF=10 Hz), the pulse-to-pulse timing jitter showed approximately 12X reduction in standard deviation, from 241 nsec for free running operation to 20 nsec with optical triggering.

Stabilization of Output Pulses from a Passively Q-switched Nd:YVO4Laser Pumped by a Continuous-wave Laser Diode

“…[1][2][3] 최근 수년간 수동형 Q-스위칭 레이저의 펄스 출력 안정화 에 대한 연구가 지속적으로 진행되었으며 [6,7] , 최근 몇몇 그 룹에서 안정된 펄스 출력을 구한 결과를 보고하고 있다. 하 지만, 이들 방법에서는 외부 조절에 의한 펄스 여기 [6,7] , 공 진기 외부에 조절 광원을 두는 방법 [8] …”

Experimental investigation of relative timing jitter in passively synchronized Q-switched lasers

“…The dominant cause of timing jitter in a single passively Q-switched laser has been attributed to pump power fluctuations [1] and noise from amplified spontaneous emission [2]. Subsequently, jitter reduction methods that increases gain modulation [1] or loss modulation [2][3][4] or self-injects a seed pulse [5] at close to the laser's repetition rate have been proposed. In particular, direct bleaching of the saturable absorber (SA) by a laser diode bar resulted in a 12 times decrease in timing jitter [4], while a self-injection seeded microchip laser achieved a 600 times reduction [5].…”

“…Subsequently, jitter reduction methods that increases gain modulation [1] or loss modulation [2][3][4] or self-injects a seed pulse [5] at close to the laser's repetition rate have been proposed. In particular, direct bleaching of the saturable absorber (SA) by a laser diode bar resulted in a 12 times decrease in timing jitter [4], while a self-injection seeded microchip laser achieved a 600 times reduction [5]. Loss modulation was applied at a slightly higher repetition rate than the laser's natural free-running repetition rate, just before the laser reaches threshold [3,4].…”

“…In particular, direct bleaching of the saturable absorber (SA) by a laser diode bar resulted in a 12 times decrease in timing jitter [4], while a self-injection seeded microchip laser achieved a 600 times reduction [5]. Loss modulation was applied at a slightly higher repetition rate than the laser's natural free-running repetition rate, just before the laser reaches threshold [3,4].…”

“…Following the definition in [4,5], timing jitter in this Letter is 1 standard deviation of the experimental data. Statistical measurements of the relative delay between the 1064 nm pulses and 946 nm pulses are obtained over 1000 samples.…”