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Q开关红宝石激光器中，红宝石棒截面积S=1cm2，棒长l=15cm，折射率为1．76，腔长L=20cm，铬离子浓度n=1．58×1019cm-3，发射截面σ=1．27×10-20cm2，光泵浦使激光上能级的初始粒子数密度n2i=1019cm-3，假设泵浦吸收带的中心波长λ=0．45μm，E2能级的寿命τ2=3ms，两平面反射镜的反射率与透射率分别为，r1=0．95，T1=0，r2=0．7，T2=0．3。试求： (1)使E2能级保持n2i=1019cm-3所需的泵浦功率Pp； (2)Q开关接通前自发辐射功率P； (3)脉冲输出峰值功率Pm； (4)输出脉冲能量E； (5)脉冲宽度τ(粗略估算)。
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