The pressure coefficient of the infra-red refractive index of germanium

Abstract In this paper measurements are reported of the pressure coefficient of the refractive index of germanium. The experimental method is based on the principle of the interference spectrum. The region covered extends from 4250 to 6250 cm -1 (0.5–0.8 eV). For long wavelengths a value is found: d n/n d P = -1.70 × 10 -6 /bar .