Black and white: a bifunctional optical standard for near-perfect white light diffuse reflection and blackbody radiation

Abstract

Durable optical standards with precise calibration are crucial for optical measurements. This study used calcium fluoride (CaF2), silicon dioxide, and hexagonal boron nitride to fabricate a bifunctional optical standard (CaF2-based bifunctional material) for diffuse reflectance and thermal emission. The average relative total diffuse reflectance of our developed material in the UV–Vis–NIR region was equal to 100.6% of the average value of the commercial PTFE standard plate. Furthermore, by exploiting the complementary absorption characteristics of its polar materials, the CaF2-based bifunctional material provided high emissivity (96.7%) in the mid-infrared region. Meanwhile, the CaF2-based bifunctional material possessed a high laser-damage threshold and excellent thermal stability compared with commercial standards. As a durable optical standard, our developed material could meet requirements for a broad range of applications, such as high-temperature optical calibration.