12 December 2006 Comprehensive study of electro-optic and passive Q-switching in solid state lasers for altimeter applications
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Laser Science and Technology Center (LASTEC), Delhi, is developing a space qualified diode pumped Nd: YAG laser transmitter capable of generating 10 ns pulses of 30 mJ energy @ 10 pps. This paper presents the results of experiments for comparative studies between electro-optic and passively Q-switched Nd: YAG laser in a crossed porro prism based laser resonator. Experimental studies have been performed by developing an economical bench model of flash lamp pumped Nd: YAG laser (rod dimension, &nullset; 3 X 50 mm). Electro-optic (EO) and Passive Q-switching were performed employing LiNbO3 crystal (9 x 9 x 25 mm) and Cr: YAG (7 &nullset; 10 mm) saturable absorber respectively. Laser output of 30 mJ was achieved in EO Q-switching mode by optimizing Pockels cell operation. More than 80 % Q-switching efficiency was achieved. However, at the same input level in passive Q-switching mode at optimized initial transmission of Cr: YAG, only 36% efficiency could be achieved. Comparative studies were made for output pulse energy at different input levels. In passive Q-switched mode, deviation from the optimum flash lamp input either stops the lasing action or leads to multiple pulsing. Thus in view of the very stringent requirements of reliability and efficiency of space-based system, the electro-optical method of Q-switching has been adopted in the design.
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Atul Bhardwaj, Atul Bhardwaj, Lalita Agrawal, Lalita Agrawal, Suranjan Pal, Suranjan Pal, Anil Kumar, Anil Kumar, "Comprehensive study of electro-optic and passive Q-switching in solid state lasers for altimeter applications", Proc. SPIE 6409, Lidar Remote Sensing for Environmental Monitoring VII, 64091D (12 December 2006); doi: 10.1117/12.694119; https://doi.org/10.1117/12.694119


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