激光谐振腔近场自再现模式分布的研究

Research on the distribution of near-field self-reproducing mode in laser resonator

根据对称共焦腔的基本衍射理论,对激光光学谐振腔的自再现模式理论进行了分析,建立了方形反射镜谐振腔和圆形反射镜谐振腔横向模式空间分布的数学模型。利用MATLAB软件,对选取确定的腔长和反射镜半径、输出波长的激光谐振腔横向模式进行了数值模拟计算仿真,模拟的结果直观、形象地反映了不同模式下的光学谐振腔的自再现模的空间分布。选取输出波长为800 nm、脉冲宽度为120 fs钛宝石飞秒激光器进行模式测试,实验验证了激光器的光场分布与仿真结果非常符合。证实建立的理论模型是正确的。

According to the basic diffraction theory of symmetric confocal cavity,the theory of self-reproducing mode of laser optical resonant cavity is analyzed,mathematical models of square mirrors resonator and circular mirror resonator for transverse mode spatial distribution are established.Numerical simulation is done for a given length of resonator, radius of mirror and the laser resonator’s transverse modes are obtained by using MATLAB software.Results of the simulation demonstrate spatial distribution of the self-reproduction model in different modes of optical resonator.In the experiment,the Ti：sapphire FS laser is selected,output wavelength and pulse width of this laser are 800 nm,1 20 fs respectively.The experiments prove that laser light field distribution is very consistent with the simulation results.It confirms that the theoretical model is correct.