Continuous wave and passively Q-switched Nd:YAG laser with a multisegmented crystal diode-pumped at 885  nm

Abstract

Mitigation of thermal effects in a 1064 nm Nd:YAG laser is demonstrated through the combination of a multisegmented crystal rod and upper laser level pumping by diode at 885 nm toward optimizing the generated beam profile. Continuous wave (cw) and passively Q-switched operation is demonstrated obtaining 7.5 W and 2 mJ at 100 Hz, respectively, with excellent beam quality. Comparison with a conventional uniform Nd:YAG rod reveals improvements of up to 64% in optical conversion efficiency and 67% in output power for retaining the beam quality. Thermal-lensing measurements validate the improved thermal management in the multisegmented crystal in conjunction with M-square values better than 1.3.

Energy scaling of passively Q-switched lasers In the Mj-range

“…At higher repetition rates the heat dissipation in the laser rods can lead to thermal effects resulting in a bad beam quality or even to stressinduced fracture of the laser crystals. Further optimization work towards high energy passively Q-switched lasers with higher repetition rates has been initiated by using multi-segmented Nd:YAG laser crystals and pumping at a wavelength of 885nm instead of 808nm [5]. In order to enable a longer energy storage time and therefore to save pump diode peak power Nd:YLF instead of Nd:YAG crystals have been used, which exhibit a fluorescence lifetime of 470µs compared to 230µs for Nd:YAG [1].…”

Cr2+:ZnSe active media with complex profiles of internal doping

“…In this case, the lack of absorption at the elements ends and a much more uniform distribution of thermal loads inside the element (comparing to surface-doped or uniformly-doped elements) allow achieving target values of lasing power with a simple and reliable laser design. Using this approach, high experimental results were obtained in a number of studies concerning ceramic and composite active elements based on yttrium aluminum garnet (YAG) doped with rare-earth elements [8][9][10], and in our studies on polycrystalline Fe 2+ :ZnSe fabricated using solid-state diffusion bonding technique (SSDB) [11]. The SSDB technique actively developed by our group allows creating active elements with unique properties, including elements with several inner doped layers and meniscus doped layer [11,12].…”