Chalcogenide glass thin film waveguides deposited by excimer laser ablation

Abstract

This paper describes the optical properties of praseodymium-doped chalcogenide (GeS 2–Ga 2S 3–CsI) thin films deposited by the pulsed laser deposition (PLD) technique using XeCl (308 nm) and KrF (248 nm) excimer lasers. Optical transmission and reflection spectra, at normal incidence, were recorded in the 200–2500 nm spectral region. The optical constants (refractive index n and extinction coefficient k) versus wavelength, as well as the film thickness, were calculated from these spectra and a computer code. The waveguiding properties of the deposited films were investigated by the prism coupling technique (m-lines spectroscopy). The presence of praseodymium in the doped chalcogenide thin film was analysed by exciting the electrons to the 1 G 4 level and collecting the photoluminescence spectrum in the 1.335 μm region. Moreover, compositional, morphological and structural characteristics of the films were obtained by Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses.