【摘要】 建立了3维温度场及应力场模型,并采用有限元分析方法对Nd:YAG作为激活介质的固体热容激光器与热稳态固体激光器进行了对比研究。激光二极管阵列距离晶体3.5 mm,阵列功率2×4.2 kW,bar间隔0.4 mm,每bar发光面积为1μm×5 mm,频率100 Hz,脉宽100μs,Nd:YAG晶体初始温度20℃,冷却水温20℃。计算结果表明:热容模式激光介质的表面温度高于中心温度,稳态模式刚好相反,稳态模式温差极值(19.8℃)是热容模式(6.4℃)的3.1倍,温度梯度极值(11.9℃/mm)是热容模式(2.46℃/mm)的4.8倍,热流密度极值(0.136 W/mm2)是热容模式(0.021 W/mm2)的6.4倍;稳态模式激光介质的表面出现张应力,中心出现压应力,热容模式则刚好相反,稳态模式压应力极值(18.27 MPa)是热容模式(12.1 MPa)的1.5倍,张应力极值(38.39 MPa)是热容模式(10.3 MPa)的3.9倍。由于晶体可以承受的压应力的破坏阈值远高于张应力,所以热容模式的固体激光器比稳态模式的固体激光器可以工作在更高的泵浦功率水平上。更多还原

【Abstract】 The temperature fields and stress fields of solid-state heat-capacity laser(SSHCL) and solid steady state laser were analyzed by finite-element analysis.The distance between LD arrays and laser crystal is 3.5 mm,LD array power 4 200 W×2,LD bars interval is 0.4 mm,While luminescence area 1 μm×5 mm,frequency 100 Hz,pulse width 100 μs,temperature of crystal and cooling water 20 ℃.The calculation reveals that the temperature on SSHCL surface is even higher than that in its interior,but the inverse phenomenon is found in solid steady state laser.The extremum temperature difference in solid steady state laser is 3.1 times than that in SSHCL,with there values being 19.8 ℃ and 6.4 ℃ respectively.The extremum temperature grads in solid steady state laser is 4.8 times than that in SSHCL,with there values being 11.9 ℃/mm and 2.46 ℃/mm respectively.The extremum heat flux in solid steady state laser is 6.4 times than that in SSHCL,with there values being 0.136 W/mm~2 and 0.021 W/mm~2 respectively.The calculation manifest that the surface of SSHCL is compressive stress and its interior is tensile,but the inverse phenomenon is found in solid steady state laser.The extremum compressive stress in solid steady state laser is 1.5 times than that in SSHCL,with there values being 18.27 MPa and 12.1 MPa respectively.The extremum tensile in solid steady state laser is 3.9 times than that in SSHCL,with there values being 38.39 MPa and 10.3 MPa respectively.Since the destructive threshold of crystal resistance against compressive stress exceed that against tensile,so SSHCL can operate at far higher burst powers than solid steady state laser.更多还原