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

Durable optical standards with precise calibration are crucial for optical measurements. This study used calcium fluoride (CaF 2 ), silicon dioxide, and hexagonal boron nitride to fabricate a bifunctional optical standard (CaF 2 -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 CaF 2 -based bifunctional material provided high emissivity (96.7%) in the mid-infrared region. Meanwhile, the CaF 2 -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.