Fe∶ZnMnSe laser active material properties at room and cryogenic temperature

摘要

Fe∶Zn(1-x)Mn(x)Se solid solution spectroscopic and laser properties were investigated in the temperature range 80-290 K. Two novel samples with different zinc - manganese (Zn-Mn) ratio described by the Mn content x (0.1 or 0.2) were used and the results were compared to the known Fe∶ZnSe crystal. The samples had a broad absorption spectra with the maximum around 3 μm and therefore an Er∶YAG laser (2.94 μm, 10 mJ, 120 ns) was used as a pump radiation source. The Fe:ZnMnSe fluorescence spectra are generally broad in the range 3.5 - 5.5 μm. In the case of Fe∶ZnMnSe x = 0.1, the fluorescence spectrum at 290 K is ranging from 3.5 to 5.5 μm. Lowering the temperature down to 80 K lead to the spectral narrowing mainly in the mid-IR part, but the fluorescence is still up to 5 μm at 80 K. In the case of Fe∶ZnMnSe x = 0.2 the fluorescence is shifted towards mid-IR up to 5.2 μm even at 80 K. The fluorescence lifetime decreases from tens of us at 80 K down to 1 us at 240 K. The laser oscillations were successfully achieved with both novel Fe∶ZnMnSe crystals in the temperature range 80- 290 K. In the case of x = 0.1, the central wavelength was ～4.2 μm at 80 K and the temperature increase up to 290 K led to almost linear increase of the wavelength up to ～4.75 μm. The tendency was similar in the case of Fe∶ZnMnSe x = 0.2: the output wavelength increased from ～4.3 μm up to ～4.8 μm with the temperature increase from 80 to 290 K. The laser spectral linewidth was about 300 ran. In comparison with the Fe∶ZnSe crystal, the laser output wavelength shift toward mid-IR region without any spectrally tunable element in the laser cavity can be clearly observed.