Interference of birefractive waves in CdGa2S4 crystals

Abstract

In СdGа2S4 crystals the Fabry–Perot and birefringence interference spectra were investigated. Spectral dependences of refraction indexes for ordinary (no) and extraordinary (ne) light waves are defined. The spectral dependence Δn=ne−no from the short and long-wavelength parts of isotropic wavelength λ0=485.7nm (300K) is determined. It is established that at λ>λ0 Δn is positive and at λ<λ0 Δn is negative. Wavelength λ0=485.7nm shifts with decreasing temperature to short-wavelengths. The phase difference of ordinary and extraordinary light waves for λ>λ0 and λ<λ0 was determined. The band in reflection spectra observed at the isotropic wavelength has a small halfwidth (～3–5Å). Another isotropic wavelength was found in the short-wavelength region (433nm) for crystals obtained by iodine transport method.