EFFECTS OF DISPERSION AND FOCUSING ON PRODUCTION OF OPTICAL HARMONICS
EFFECTS OF DISPERSION AND FOCUSING ON PRODUCTION OF OPTICAL HARMONICS
复制标题
DOI：
10.1103/physrevlett.8.21
复制
发表时间：
1962-01-01
影响因子：
8.6
通讯作者：
NISENOFF, M
中科院分区：
文献类型：
--
作者：
MAKER, PD;SAVAGE, CM;NISENOFF, M
最近，Franken 等人演示了利用压电晶体电敏感性的非线性来产生光学谐波。使用经典方法，我们可以认为激光红光产生偶极子的空间排列，而偶极子又辐射蓝光。对于平面波入射到厚度为 x 的晶体的情况，向前辐射的蓝光强度为 8= 2wcP'(k/hk)'sin2hkx, n, k= Ik-2k I,'b''= b 其中 k~ 和 ky 分别是红光和蓝光的波矢，P 是诱导的蓝色偏振的幅度。 sin Akx 项的产生是由于晶体色散导致红色辐射（蓝色偏振）和蓝色辐射之间的相移。这种失相限制了有效晶体厚度。这些色散效应已在石英中得到证实。红宝石激光束穿过光学平面平行的石英片，使用 CuSO4 溶液滤光器和光栅单色仪滤除红光，并通过光电测量蓝光强度。样品通过绕其 z 轴旋转而向光束倾斜，从而增加了光学厚度并生成如图 1 所示的曲线。当减少到厚度变化时，连续最大值之间的间距与计算值 13. 9 微米非常吻合。%e 能够平衡磷酸二氢钾 (KDP) 中色散的影响。将谐波极化与外加电场相关的矩阵元素，受对称性和电磁能守恒的限制，适用于 KDP：
Recently Franken et al.'demonstrated the generation of optical harmonics utilizing the nonlin-earity in the electric susceptibility of piezoelec-tric crystals. Using a classical approach one can think of the laser red light generating a spatial arrangement of dipoles which in turn radiate blue light. For the case of a plane wave incident on a crystal of thickness x, the intensity of the blue light radiated in the forward direction is 8= 2wcP'(k/hk)'sin2hkx, n, k= Ik-2k I,'b''= b where k~ and ky are the wave vectors for the red and blue lights, respectively, and P is the magni-tude of the induced blue polarization. The sin Akx term arises because of dephasing between red ra-diation (blue polarization) and blue radiation, due to dispersion of the crystal. This dephasing lim-its the effectivecrystal thickness. These disper-sive effects have been demonstrated in quartz. A ruby laser beam was passed through an opti-cally plane-parallel quartz platelet, the red light filtered out using a CuSO4 solution filter and a grating monochrometer, and the blue lightinten-sity measured photoelectrically. The sample was inclined to the beam by rotation about its z axis, thus increasing the optical thickness and generat-ing thecurve shown in Fig. 1. The spacing be-tween successive maxima when reduced to thickness changes agreed well with the calculatedval-ue, 13. 9 micr ons.% e were able to balance out the effect of dis-persion in potassium dihydrogen phosphate (KDP). The matrix elements relating harmonic polariza-tion to applied electric field, as limited by sym-metry and conservation of electromagnetic ener-gy, are for KDP: