The 2.7 –3 μm mid-infrared lasers have wide applications in medicine, scientific research, and atmospheric detection.
The recent study was conducted by SUN Dunlu's research group at Anhui Institute of Optics and Fine Mechanics (AIOFM), Hefei Institutes of Physical Science. A 2.79 μm radiation resistant laser was achieved with high energy and repetition rate, and that a dual wavelengths polarization laser operated at 2.71 and 2.73 μm was also realized.
On the basis of the previous research work, this group further investigated the laser performance of Er,Pr:GYSGG laser crystal by LD side-pumping. A maximum output power of 8.86 W was achieved at 125 Hz and 200 μs pulse widths. The results indicated that a high performance 2.79 μm laser could be realized on the Er,Pr:GYSGG radiation resistant crystal by deactivation and LD side-pumping.
In addition, they demonstrated a LD end-pumped Er:YAP laser with dual-wavelength outputs of 2710 and 2728 nm. The thermal analysis, laser performance and beam quality for different size Er:YAP crystals presented that a proper size was beneficial to decrease the thermal lensing effect and improve the laser efficiency.
Moreover, a high optical quality Er,Pr:YAP were also grown by Czochralski method for the first time.
The study suggested that the deactivator ions Pr3+ was beneficial to decrease the laser threshold and increase the laser efficiency. But the doping concentration of Er3+ and Pr3+ ions still needs to be further optimized.
These lasers with high peak power and high repetition rates operated at 2.7 –3 μm wavelength region can be applied in optoelectronic countermeasure and nonlinear optics.
Link to the paper: Growth, structure and spectroscopic properties of Er,Pr:YAP laser crystal
2.7 μm dual-wavelength laser performance of LD end-pumped Er:YAP crystal
Laser performance of a 966 nm LD side-pumped Er,Pr:GYSGG laser crystal operated at 2.79 μm
Schematic diagram of the Er,Pr:GYSGG crystal laser pumped by 966 nm LD arrays. Inset: side-pump symmetry. (Image by ZHAO Xuyao)
Laser output power versus input power in different repetition rates. (Image by ZHAO Xuyao)
Laser beam diameter versus propagation distance. (Image by ZHAO Xuyao)
Photograph of the Er:YAP crystals and schematic of laser pumped by the ~970 nm LD with CW or pulse modes. (Image by QUAN Cong)
Laser output power versus pump power for different size crystals. (a) 973 nm LD pump in CW mode and (b) 962 nm LD pump in pulse mode. (Image by QUAN Cong)
Beam diameter versus propagation distance for three Er:YAP crystals. (a) 1×1×5 mm3 crystal; (b) 2×2×5 mm3 crystal; (c) 3×3×5 mm3 crystal. (Image by QUAN Cong)
Fluorescence decay curves of the Er:YAP and Er,Pr:YAP crystals. (Image by QUAN Cong)