Biography
Prof. Xinlu Zhang
Prof. Xinlu Zhang
Tianjin Polytechnic University, China
Title: Mid-infrared Ho:YAG/BaWO4 and YVO4 intracavity Raman lasers resonantly pumped by a Tm:YLF laser at 1908 nm
Abstract: 
Stimulated Raman scattering (SRS) in crystalline materials has been a very important nonlinear frequency conversion method. Solid state Raman lasers based on the SBS effect can generate a new wavelength of Raman laser, which is difficult to access with direct laser oscillation. The output wavelength of a Raman laser depends on the wavelength of fundamental laser and the Raman frequency shift of Raman crystal. With the development of high quality Raman crystals, solid state Raman lasers have attracted more and more attentions. Among these known Raman crystals, the BaWO4 and YVO4 are two kinds of excellent Raman crystals which are widely investigated, due to high thermal conductivity and high optical damage threshold.
In this paper, we report the mid-infrared intracavity Raman lasers based on BaWO4 and YVO4 Raman conversion in a resonantly pump actively Q-switched Ho:YAG laser for the first time, to the best of our knowledge. The output performances of the BaWO4 and YVO4 Raman lasers are investigated in detail. For the 2640 nm BaWO4 Raman laser, at a pulse repetition frequency of 5 kHz, the maximum average output power of 473 mW is obtained with a 9.8 W incident pump power at 1.91 μm. At a repetition frequency of 1 kHz, the threshold pump power is as low as 2.1 W. At the pump power of 3.3 W, the maximum pulse energy, the shortest pulse width, and the highest peak power are 93 uJ, 7.3 ns, and 12.7 kW, respectively. Compared with the BaWO4 Raman laser, the 2518 nm YVO4 Raman laser has a higher threshold pump power of 5.1 W at the repetition frequency of 1 kHz. The maximum pulse energy, the shortest pulse width, and the highest peak power are 265 uJ, 10 ns, and 26.2 kW, respectively.
Biography: 
Xinlu Zhang obtained his Bs degree in physics from Jilin University, China in 1995 and the Ms and PhD degrees from Harbin Institute of Technology, China in 2001 and 2005, respectively. In 1995, he joined Harbin Engineering University as an Assistant professor. In 2005, he became a Professor and a group leader. From 2016, he joined the optoelectronic information science and engineering department of Tianjin Polytechnic University, China. He is presently interested in mid-infrared solid state lasers (with Tm/Ho doped, and Tm-Ho codoped crystals as gain media), fiber lasers, and nonlinear frequency conversion. Dr Zhang has published more than 100 journal papers in Opt. Lett., Opt. Express et. al.