Pumping at 885 nm from thermally excited ground-state levels directly to the Nd:YAG upper lasing level is experimentally demonstrated by use of a Ti:sapphire pump laser. This approach utilizes thermal energy contained within the laser medium to provide part of the pump energy required to achieve population inversion. Slope efficiency increased by 12% compared with traditional pump band excitation (λ<sub>pump</sub> = 808 nm) and by 7% compared with ground-state direct pumping (λ<sub>pump</sub> = 869 nm). The combined transition from the first and second thermally excited Stark components of the ground state (<sup>4</sup><i>I</i><sub>9/2</sub>) to the upper lasing level (<sup>4</sup><i>F</i><sub>3/2</sub>) has characteristics that make thermally boosted pumping a suitable candidate for use with diode lasers: reasonable absorption (1.8 cm<sup>−1</sup>) and bandwidth (2.7 nm FWHM). A model suggests that, compared with traditional 808-nm pumping, heat could be reduced by 40% by use of thermally boosted pumping.
© 2000 Optical Society of America
(140.3380) Lasers and laser optics : Laser materials
(140.3480) Lasers and laser optics : Lasers, diode-pumped
(140.3530) Lasers and laser optics : Lasers, neodymium
(140.3580) Lasers and laser optics : Lasers, solid-state
(140.6810) Lasers and laser optics : Thermal effects
Raphael Lavi and Steven Jackel, "Thermally Boosted Pumping of Neodymium Lasers," Appl. Opt. 39, 3093-3098 (2000)