Broadband Second-Harmonic Generation in the Near-Infrared Region in a Tapered Zinc Selenide Slab Using Total Internal Reflection Quasi-Phase Matching

Abstract

We analytically describe the concept of broadband second-harmonic generation in the near-IR region in an isotropic tapered semiconductor slab made of zinc selenide. A computer-aided simulation has been carried out to determine the possibility of generating broadband second-harmonic intensity when broadband fundamental laser radiation is allowed to undergo total internal reflection inside the tapered semiconductor slab. The simulated results indicate an extremely broad spectral bandwidth of 557 nm centered at 4.05 µm (3.812 to 4.369 µm) in a 10-mm-long slab with a conversion efficiency of 0.02%. The losses due to absorption and surface roughness of the semiconductor material have been considered in the analysis. The effects of variations in the temperature, length, and tapering angle of the semiconductor slab have been studied for the generated second-harmonic radiation.

Eye safety implications of high harmonic generation in zinc selenide

“…Polycrystalline zinc selenide (ZnSe) is utilized for applications ranging from harmonic generation [1] to broadband frequency conversion [2] due to its unusually strong nonlinear properties. Quasi-phase matching in polycrystalline ZnSe's crystal grains [3] has been used to explain enhanced sum [4] and difference frequency generation [3], second-harmonic generation [2,4,5], and extended phase matching conditions allowing for broadband frequency conversion [4,5].…”

“…Polycrystalline zinc selenide (ZnSe) is utilized for applications ranging from harmonic generation [1] to broadband frequency conversion [2] due to its unusually strong nonlinear properties. Quasi-phase matching in polycrystalline ZnSe's crystal grains [3] has been used to explain enhanced sum [4] and difference frequency generation [3], second-harmonic generation [2,4,5], and extended phase matching conditions allowing for broadband frequency conversion [4,5]. Filamentation studies report that high intensity pulses generate visible blue filaments near the front surface of ZnSe windows [6,7] and that filamentation in ZnSe can result in the generation of a broadband supercontinuum, which can be seen in spectra between the strong harmonic peaks [5,8].…”