Measurement of Refractive Index of GaP Crystal over a Large Temperature Range Using Interferometry

• Published in: Crystal research and technology (1979) Vol. 35; no. 2; pp. 221 - 228
• Main Authors: Yin, D.C., Inatomi, Y.
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag Berlin GmbH 01.02.2000; WILEY‐VCH Verlag Berlin GmbH; Wiley-VCH
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; interferometers; non-destructive testing (optical method); optical constants; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; semiconductors; semiconductors; non‐destructive testing (optical method); thermal expansion; Thermal expansion; Temperature dependence; Gallium phosphides; Monocrystals; Inorganic compounds; Semiconductor materials; Refractive index; Experimental study
• ISSN: 0232-1300; 1521-4079
• DOI: 10.1002/(SICI)1521-4079(200002)35:2<221::AID-CRAT221>3.0.CO;2-8

The refractive index of GaP single crystal was measured through room temperature (300K) to 1200K at a wavelength of 780 nm by using an interferometry with a laser diode. To get a more accurate result, the thermal expansion coefficient of GaP crystal, which would be one parameter for the measurement of the refractive index, was measured by a diratometer equipped with laser interferometry against temperature in the range from room temperature to 973K. It was confirmed that the linear thermal expansion coefficient was a function of temperature. In this report, an empirical function was obtained to calculate the refractive index at any temperature for GaP crystal. The result shows that the refractive index of GaP varies from 3.1907 to 3.3354 in the temperature range from 300K to 1200K at the wavelength of 780nm.