Two-photon absorption and nonlinear refraction of lanthanum sulfide-gallium sulfide glasses

Abstract

The two-photon absorption coefficient (β) and nonlinear refractive index (γ) of the binary La2S3–Ga2S3 and ternary MS–La2S3–Ga2S3 (MS=Ag2S and Na2S) glasses were measured at 532 nm by the Z-scan method. The β of the glasses was ∼40 cm GW−1 and nearly unchanged with La2S3 content in the binary glasses, while it increased, or decreased with the substitution of Ag2S, or Na2S, respectively, for La2S3 in the ternary glasses. The γ of the glasses increased, with the rising La2S3 content in the binary glasses, and increased, or decreased with the addition of Ag2S, or Na2S, respectively, in the ternary glasses. The results were compared with the third-order nonlinear optical properties measured by third harmonic generation and discussed on the basis of their linear optical properties.