Instead of using an expensive modelocked Nd:YAG laser as the seed source, NASA Goddard Space Flight Center (Greenbelt, MD) and American University (Washington, DC) scientists used commercially available laser diodes to build a small-footprint regenerative amplifier suited for ground-based satellite laser-ranging applications.
With a goal of creating 1 mJ of 532 nm light at a 2 kHz repetition rate with pulsewidths of less than 200 ps, the setup begins with a 1064 nm narrowband laser diode driven in short-pulse mode (0.2–0.4 ns seed pulsewidths). The input enters the amplifier gain unit consisting of two Brewster-cut Nd:YAG laser slabs oriented 90º to each other to simplify optical correction and create a symmetrical thermal lens effect and each pumped with an 808 nm laser-diode array. Laser-diode temporal seeding allows pulse energy to build on successive passes through the amplifier until cavity gains and losses equalize, creating 2.1 W (82 dB gain) of 532 nm light after passing through a lithium niobate crystal. Unlike commercial amplifier systems, the laser-diode seed pulses allow the pulse shape to be customized and stay unaffected by cavity length or amplifier gain. Finally, the laser-diode-based configuration can produce adjustable pulsewidths through the addition of multiple seed diodes coupled into low-cost fiber-optic combiners. Contact Demetrios Poulios at [email protected].
Gail Overton | Senior Editor (2004-2020)
Gail has more than 30 years of engineering, marketing, product management, and editorial experience in the photonics and optical communications industry. Before joining the staff at Laser Focus World in 2004, she held many product management and product marketing roles in the fiber-optics industry, most notably at Hughes (El Segundo, CA), GTE Labs (Waltham, MA), Corning (Corning, NY), Photon Kinetics (Beaverton, OR), and Newport Corporation (Irvine, CA). During her marketing career, Gail published articles in WDM Solutions and Sensors magazine and traveled internationally to conduct product and sales training. Gail received her BS degree in physics, with an emphasis in optics, from San Diego State University in San Diego, CA in May 1986.