The Influence of Excitation Density on Laser Induced White Lighting of Wide-Band-Gap Semiconductor ZnSe:Yb Polycrystallite Ceramics

Abstract

The irradiation of ZnSe:Yb polycrystalline ceramics by focused beam of a CW 975 nm laser diode in vacuum conditions leads to generation intense white light in visible range. The emission band was centered at 630 nm. The intensity of white emission increased exponentially with the power density of incident laser light. The influence of excitation power density on generation of broadband emission was investigated. It was found that with increasing excitation power density the total intensity and the slope of exponential enhancement of white light significantly increase. Moreover, for the highest excitation power density there appeared by excitation threshold. The impact of excitation density on white laser induced white emission (LIWE) was discussed in terms of multiphoton excitation and avalanche ionization