平顶高斯光束谐波场的横向分布

Field Distribution of the SHG and THG Wave on the Flattened Gaussian Beam

对平顶高斯光束用于倍频和混频后的谐波场场强分布进行了理论计算,模拟了相同基波峰值强度下,不同阶数和不同偏振分量比的平顶高斯光束在长度为5mm的非线性晶体CsLiB6O10上的Ⅰ类、Ⅱ类倍频光场及Ⅱ类混频光场的横向分布曲线,并将其与基波场分布进行了比较,得到了谐波场仍为均匀平顶分布形式,但出现了横向光斑压缩现象,且基波光束的阶数愈高,横向压缩现象越弱;阶数相同,偏振分量不同的基波产生的谐波场光斑大小基本相同,但光场强度不同。

Here,the field distribution of the flattened Gaussian beam's second harmonic generation(SHG)and the third harmonic generation(THG)on the crystal CsLiB_6O_(10)is theoretically calculated;at the same time,we simulate the type-Ⅰ and type-Ⅱ SHG and THG field distribution curves versus the order of the flattened Gaussion beam and the pumping light polarization rate under the same crystal length(5 mm)and the same pumped power intensity,and compare it with that of the pumping wave.We prove that the field distribution of the harmornic wave across the waist plane is still flattened but a little shrunk.