The intrinsic features involving a circularly symmetric beam profile with low divergence, planar geometry as well as the increasingly enhanced power of vertical-cavity surface-emitting lasers （VCSELs） have made the ...The intrinsic features involving a circularly symmetric beam profile with low divergence, planar geometry as well as the increasingly enhanced power of vertical-cavity surface-emitting lasers （VCSELs） have made the VCSEL a promising pump source in direct end bonding to a solid-state laser medium to form the minimized, on-wafer integrated laser system. This scheme will generate a surface contact pump configuration and thus additional end thermal coupling to the laser medium through the joint interface of both materials, apart from pump beam heating. This paper analytically models temperature distributions in both VCSEL and the laser medium from the end thermal coupling regarding surface contact pump configuration using a top-emitting VCSEL as the pump source for the first time. The analytical solutions are derived by introducing relative temperature and mean temperature expressions. The results show that the end contact heating by the VCSEL could lead to considerable temperature variations associated with thermal phase shift and thermal lensing in the laser medium. However, if the central temperature of the interface is increased by less than 20 K, the end contact heating does not have a significant thermal influence on the laser medium. In this case, the thermal effect should be dominated by pump beam heating. This work provides useful analytical results for further analysis of hybrid thermal effects on those lasers pumped by a direct VCSEL bond.展开更多
A multistage amplifier system based on high-power end-pumped two-segmented Nd:YVO4is developed,which realizes the effective beam quality management in high-power lasers.Because of the severe thermal effect caused by h...A multistage amplifier system based on high-power end-pumped two-segmented Nd:YVO4is developed,which realizes the effective beam quality management in high-power lasers.Because of the severe thermal effect caused by high-power end pumping,both the appropriate crystal and beam filling factor(the ratio of the laser beam radius to the pump beam radius)are important in the amplifier.The multisegmented doped crystal is controlled in cooperation with the beam filling factor to realize high output power and maintain good beam quality.To study the thermal effect in the end-pumped crystal,the temperature distributions of end-pumped single-segmented and two-segmented Nd:YVO4are theoretically calculated.In the experiment,a probe laser is employed to measure the spherical aberration coefficient and the beam quality of the laser at the rear end of the two end-pumped crystals,respectively,and the experimental results are in good agreement with the theoretical results.In the power amplification,a seed laser is employed in the experiment.The appropriate gain medium and beam filling factor are determined by considering the spherical aberration coefficient,beam quality,and power extraction efficiency.Based on the reasonable layout of the power amplification for each stage amplifier,the multistage amplifier system outputs a 280.2 W picosecond laser with the beam quality factors of M_(x)^(2)=1.28 and M_(y)^(2)=1.32.展开更多
文摘The intrinsic features involving a circularly symmetric beam profile with low divergence, planar geometry as well as the increasingly enhanced power of vertical-cavity surface-emitting lasers （VCSELs） have made the VCSEL a promising pump source in direct end bonding to a solid-state laser medium to form the minimized, on-wafer integrated laser system. This scheme will generate a surface contact pump configuration and thus additional end thermal coupling to the laser medium through the joint interface of both materials, apart from pump beam heating. This paper analytically models temperature distributions in both VCSEL and the laser medium from the end thermal coupling regarding surface contact pump configuration using a top-emitting VCSEL as the pump source for the first time. The analytical solutions are derived by introducing relative temperature and mean temperature expressions. The results show that the end contact heating by the VCSEL could lead to considerable temperature variations associated with thermal phase shift and thermal lensing in the laser medium. However, if the central temperature of the interface is increased by less than 20 K, the end contact heating does not have a significant thermal influence on the laser medium. In this case, the thermal effect should be dominated by pump beam heating. This work provides useful analytical results for further analysis of hybrid thermal effects on those lasers pumped by a direct VCSEL bond.
基金supported by the National Natural Science Foundation of China(No.62105179)the National Key R&D Program of China(No.2023YFE0199000)the Baima Lake Laboratory Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(No.LBMHZ24F050001)。
文摘A multistage amplifier system based on high-power end-pumped two-segmented Nd:YVO4is developed,which realizes the effective beam quality management in high-power lasers.Because of the severe thermal effect caused by high-power end pumping,both the appropriate crystal and beam filling factor(the ratio of the laser beam radius to the pump beam radius)are important in the amplifier.The multisegmented doped crystal is controlled in cooperation with the beam filling factor to realize high output power and maintain good beam quality.To study the thermal effect in the end-pumped crystal,the temperature distributions of end-pumped single-segmented and two-segmented Nd:YVO4are theoretically calculated.In the experiment,a probe laser is employed to measure the spherical aberration coefficient and the beam quality of the laser at the rear end of the two end-pumped crystals,respectively,and the experimental results are in good agreement with the theoretical results.In the power amplification,a seed laser is employed in the experiment.The appropriate gain medium and beam filling factor are determined by considering the spherical aberration coefficient,beam quality,and power extraction efficiency.Based on the reasonable layout of the power amplification for each stage amplifier,the multistage amplifier system outputs a 280.2 W picosecond laser with the beam quality factors of M_(x)^(2)=1.28 and M_(y)^(2)=1.32.
