Fig. 1. Schematic of optical path for 1 kHz Ho∶YAG Q-switched laser^[23]

Fig. 2. Average output power of second stage amplifier versus pump power ^[23]

Fig. 3. Schematic of optical path for 10 kHz Ho∶YAG Q-switched laser^[24]

Fig. 4. M² and transverse 2D beam profile at 231 W ^[24]

Fig. 5. Output power of second stage amplifier ^[24]

Fig. 6. Schematic of optical path for 20 kHz Ho∶YAG Q-switched laser^[25]

Fig. 7. Average output powers of R-S-S and T-S-S amplifiers ^[25]

Fig. 8. Schematic of 102 W ZGP MOPA system with physical map of ZGP crystal with aperture of 15 mm×15 mm shown in inset^[29]

Fig. 9. Output power of ZGP OPA ^[29]

Fig. 10. Schematic of optical path for 161 W ZPG MOPA system^[25]

Fig. 11. Average output power of ZGP OPA ^[25]

Fig. 12. Average output power of idler light at different wavelengths with transmission spectrum of ZGP crystal shown in inset ^[30]

Fig. 13. Schematic diagram of 11.4 W 8.3 μm cascaded ZGP OPA^[31]

Fig. 14. Output power of 8.3 μm idler light from ZGP OPA versus 2.8 μm pump power ^[31]

Fig. 15. Schematic of optical path for 5.12 W mid-infrared BGSe OPO^[35]

Fig. 16. M² of ring cavity BGSe OPO signal light at 3.04 W ^[35]

Fig. 17. Schematic of optical path for narrow bandwidth BGSe OPO＋ZGP OPA system^[36]

Fig. 18. Spectra of signal light and idler light output from ZGP OPA^[36]

Fig. 19. Schematic of optical path for seed-injection CdSe OPO^[40]

Fig. 20. Output power of 10.1 μm idler light versus pump power under different injection seed laser powers ^[40]

Fig. 21. Characteristics of idler light at 11 μm from seed-injection CdSe OPO^[41]. (a) Spectrum; (b) M² at 802 mW