放电型高增益KrF激光器非稳腔的研究

给出了放电型高增益非稳腔KrF激光器具有衍射极限的激光模式建立的时间与非稳腔放大率和腔长之间的关系。实验对放大率M=8,腔长L=1.75m和放大率M=13.3,腔长L=1.85m的正支共焦非稳腔在不同增益下输出光的发散角进行了测量。充电电压为30kV,发散角分别是39倍衍射极限和33倍衍射极限。当充电电压降至26kV,即降低腔内介质的增益时,它们的发散角分别是20倍和5倍衍射极限。表明了具有衍射极限的模式建立时间受放大率、腔长以及饱和效应的影响。要得到衍射极限光,其衍射极限光的建立时间必须小于饱和时间。

UNSTABLE RESONATOR STUDY FOR A HIGH GAIN KrF DISCHARGE LASER

The relationship between the magnification and cavity length to the set up time of the laser mode with diffraction limited divergence in high gain KrF laser is given, and its effect on the output beam is studied. The divergence of output beam from positive branch confocal unstable resonator with M = 8, L = 1.75m and with M = 13.3, L = 1.85m is measured. Under the 30kV charge voltage, the divergences of resonator M=8 and M=13.3 are 39 and 33 times diffraction -limited divergence respectively, and as charge voltage is 26kV, they are 20 and 5 times individualy. The results of the experiment indicated that the set up time of the diffraction limited mode in the resonator is influenced by magnification, cavity length and the gain saturation effect of the laser. It is necessary that the set-up time of the diffraction limited mode must be less than the saturation time of the light in the cavity in order to get a diffraction -limited mode.