Linear optical characterization of meter-size zinc sulfide polycrystal

Zinc sulfide (ZnS) has promising linear and nonlinear optical properties and has shown important applications in military and modern devices. In this work, coupled with the chemical vapor deposition (CVD) method and hot isostatic pressing (HIP), we successfully grew a high-transmittance and low-absorption-coefficient polycrystalline ZnS with a size of 1 m x 2 m and a thickness of 20 mm. The linear optical properties, including the UV-vis-NIR transmission spectrum, infrared spectrum, and refractive index, were systematically characterized, which shows that the present ZnS polycrystal exhibits a wide transmission range from 0.34 to 15.00 mu m, covering two important atmospheric windows. Moreover, its Sellmeier equation was achieved and fitted as a modification of previous studies. According to the refractive index and transmission spectrum, optical loss was calculated to be < 3.5% from 1 to 10 mu m. All the results indicate that the present sample has comparable properties with the single crystals and should have potential applications as a functional material.