Study On The Continuous Wave And Acousto-optic Q-switched Laser Characteristics Of Disordered Garnet Crystal Yb:CNGG

Among the numerous laser crystals,Ytterbium(Yb)doped calcium niobium gallium garnet(Yb:CNGG)was focused by researchers in recent years.As a disordered laser crystal,it possesses,to some extent,the advantages of laser glasses such as broad absorption and emission bands,and the advantages of ordinary laser crystals such as relatively high thermal conductivities.To research the laser property of this type crystal systematically is significant in the development of new solid-state lasers.In these works,we used the Yb:CNGG crystal as the laser gain medium,comprehensive and deep researched its continuous wave laser characteristics,acousto-optic Q-switched characteristics and the wavelength tunable characteristics by a simple plano-concave resonator,obtained a number of significant results.We researched the spectrum characteristics of Yb:CNGG crystal,and calculated its small signal absorption characteristics.We compared the the effects of different cavity length,transmittance of output mirror,and the wavelength of pump beam.Under the 935 nm pumping,we got the highest output power of 3.36 W with the best transmittance of10%,corresponding to the slope efficiency of 24%.And with the 975 nm pump,we got the output power of 3.52 W,with a slope efficiency of 38.9% at the best transmittance of20%.We report the repetitively acousto-optically Q-switched laser operation of Yb:CNGG under the pulse repetition rate(PRF)from 50 kHz to 1 kHz.The emission wavelengths around 1030-1035 nm.At the PRF=50 kHz,the highest average output power is 1.96 W,with a slope efficiency of 16%.The highest peak power of 20.53 kW is generated at pulse repetition rate of 1 kHz,with pulse width 12.1 ns and pulse energy 269 μJ.We achieved the Yb:CNGG wavelength tuning under the transmittance of 0.5% by a1 mm thick birefringent filter.The tuning range is from 1035 nm to 1089 nm.