Experimental results on the first miniature Nd:YAG laser end-pumped by a single incoherent infrared-emitting diode are given. Laser operation was verified by measurements of relaxation oscillations, angular divergence, wavelength, and nonlinear output. In order to emit in the 0.81- μm pump band of Nd:YAG, the GaAs 1-x P x diode required cooling to 88 K (-185°C). Cooling the diode increased its efficiency while cooling the rod decreased the pump power necessary to reach threshold. With both laser mirrors highly reflecting at 1.06 μm, the maximum pulse power P_{D}^{th} emitted by the diode at threshold was 6.2 ± 1.2 mW. The diode power required for laser threshold at room temperature was derived and compared with more recent experiments. Miniature size and long-lived solid-state components make this laser attractive for further development.

Single-diode end-pumped Nd:YAG laser

The finite lifetime of conventional pump sources and the limited power available in a spacecraft make solar pumping of a space-borne optical communication laser an attractive approach. This paper describes a Nd: YAG laser in which solar energy is used directly to produce the population inversion. Sunlight is collected by a 24-inch diameter mirror and focused into the end of the laser rod. This "end pumping" configuration permits "side pumping" by lamps or light-emitting diodes when the sun is not visible from the satellite. The laser rod is soldered to a heat sink and cooled by direct conductive cooling, a technique which is compatible with spacecraft application. A multi-nlode output of 1.5 watts has been obtained with this laser. A specially-designed, low-loss LiNbO 3 phase modulator is used to mode lock the laser and produce an output pulse-train which is suitable for use in a pulse-code-modulation optical communication system.

http://ieeexplore.ieee.org/iel5/9937/31693/01476768.pdf

C.B. Hitz

Papers

A mode-locked, sun-pumped Nd:YAG laser