Cr:ZnMgSe laser pumped by 1.7 μm Er:YLF radiation

摘要

The aim of the presented work is to demonstrate operation of a CnZnMgSe laser pumped by a Er:YLF laser. Laser output characteristics are compared with a Cr:ZnSe laser operated under similar conditions. Pumping 1.73 μm Er:YLF laser (Er:YLF rod 80 mm long, flashlamp-pumped) radiation was focused into the Cr:ZnMgSe or Cr:ZnSe active crystal (thickness 4.9 mm and 2.2 mm, respectively; absorption coeficient 4.5 and 10.9 cm~(-1) @ 1.73 μm, respectively). The active crystal was inserted into the stable non-selective optical resonator or into the resonator with a wavelength-selective element. The 65 mm long non-selective resonator was formed by a flat dichroic pumping mirror (HT @ 1.74 μm, HR @ 2.4 μm), and a concave output coupler (R = 82 % @ 2.4 μm, r = 500 mm). The maximal output pulse energy and efficiency with respect to the absorbed pumping energy were measured 5.8 mJ and 36 % for the Cr:ZnMgSe laser, and 10.2 mJ and 76 % for the Cr:ZnSe laser. Central emission wavelength was 2.46 μm and 2.4 μm for the Cr:ZnMgSe and Cr:ZnSe laser, respectively. The spectral line-width was about 55 nm in both cases. In the case of 80 mm long output wavelength selective resonator the MgF_2 Lyot filter was inserted between the active crystal and the output coupler. Output wavelength tuning was obtained in the range 2.35 - 2.55 μm and 2.29 - 2.53 μm for the Cr:ZnMgSe and Cr:ZnSe laser, respectively. Maximum output energy was ～ 4 mJ in both cases.