PbS Doped Silicate Glasses for Radiation Control in Near IR Lasers: Optical and Structural Characterization

Abstract—Structural regularities of lead sulfide doped glasses containing narrow gap PbS nanocrystals have been studied. The precipitation of the semiconductor phase is confirmed by X-ray diffraction data. Angular dependencies of SAXS intensity of the studied samples as well as their TEM images clearly show formation of nearly monodisperse ensemble of PbS nanocrystals. Keywords—PbS doped slicate glasses; structural characteri-zation; PbS nanocrystals (NCs); low NCs size dispersion; I. I NTRODUCTION The problem of controlling output radiation in compact diode-pumped solid-state and fiber lasers demands elaboration of new materials that are able to operate as effective saturable absorbers. Inorganic glasses containing nanometer size semiconductor NCs smaller than the Bohr radius of the bulk exciton are convenient for these purposes. Actually, strongly confined PbS NCs demonstrate a discrete absorption spectrum, with exciton absorption band being tuned over a wide spectral range 1.0 - 2.5 µ due to quantum size effect. For the past few years PbS-doped glasses have been successfully used for passive Q-switching and mode locking in a variety of near-IR lasers [1]. II. EXPERIMENTAL 2.1. Samples and methods The base glass composition of potassium-zinc-aluminum-silicate system was used for preparation of PbS NCs doped glasses. In order to precipitate crystalline PbS phase in the glass volume we used two-step annealing procedure. The primary heat treatment temperature was 480 °C (below the base glass transition temperature T