Study on the third and second-order nonlinear optical properties of GeS2-Ga2S3-AgCl chalcohalide glasses

Third-order optical nonlinearities, chi((3)) of GeS2-Ga2S3-AgCl chalcohalide glasses have been studied systematically utilizing the femtosecond time-resolved optical Kerr effect (OKE) technique at 820nm, showing that the value of.(3) enhances with increasing atomic ratio of (S+ Cl/2)/(Ge+Ga). From the compositional dependence of glass structure by Raman spectra, a strong dependence of.(3) upon glass structure has been found, i.e. compared with [ClxS3-xGe(Ga)-Ge(Ga) S3-xClx] ethane-like s.u. as the structural defectiveness, [Ge(Ga) S4-xClx] mixed tetrahedra make greater contribution to the enhancement of.(3). The maximum.(3) among the present glasses is as large as 5.26 x 10(-13) esu (A1 (80GeS(2)-10Ga(2)S(3)-10AgCl)), and the nonlinear refractive index (n(2)) of A1 glass is also up to 4.60 x 10(-15) cm(2)/W. In addition, using Maker fringe technique, SHG was observed in the representative A1 glass poled by electron beam (25 kV, 25 nA, 15 min), and the second-order optical nonlinear susceptibility is estimated to be greater than 6.1 pm/V. There was no evident structural change detected in the as-prepared and after irradiated A1 glass by the Raman spectra, and maybe only electronic transition and distortion of electron cloud occurred in the glasses. The large third/second-order optical nonlinearities have made these GeS2-Ga2S3-AgCl chalcohalide glasses as promising materials applied in photoelectric fields. (c) 2007 Optical Society of America.