First observation of second-harmonic reflection from anisotropic crystal surfaces (Conference Presentation)

Abstract

Bloembergen and Pershan [1] predicted that along with the transmitted second harmonic beam, a beam at the second harmonic frequency is also reflected from the incident surface of the crystal. Experimental verification of the laws for second harmonic reflection (SHR) in isotropic crystals of GaAs [2] were presented thereafter. SHR from crystalline GaAs under picosecond laser irradiation at 532 nm was demonstrated [3]. To our knowledge, the phenomenon of SHR has not been demonstrated before for anisotropic crystals, nor has it been considered theoretically. Using a 10 picosecond duration laser at 1064 nm at an angle of incidence of 45° upon crystals of CdSiP2 (010), ZnGeP2 (010) and GaAs (110), we observed SHR at 532 nm, which was detected using a silicon detector (Laser Probe RjP-765). The generated SHR depended on the square of the incident irradiance. The dependence of SHR energy on the polarization direction of the incident beam and on the orientation direction of the (001)-axis of the crystal around the sample normal was determined. The detailed theory for Maker fringes in anisotropic media presented earlier [4] was extended to the case of uniaxial crystals of 4 2m symmetry and to isotropic crystals for the determination of the amount of SHR predicted.