Determination of the refractive index of air and its variation with temperature and pressure using a Mach–Zehnder interferometer.

Autor: Shaheen, Mohamed E., Abdelhameed, Salma T., Abdelmoniem, N. M., Hashim, Hisham M., Ghazy, Riyad A., Abdel Gawad, Sayed A., Ghazy, Ahmed R.
Zdroj: Journal of Optics (09728821); Jul2024, Vol. 53 Issue 3, p2219-2228, 10p
Abstrakt: In this study, we determined the refractive index of the air at different pressures and temperatures using a home-built Mach–Zehnder interferometer. The pressure and temperature were controlled using a home-built gas flow system and a temperature controller. A He–Ne laser operating at wavelengths of 632.8 nm was used to illuminate the Mach–Zehnder interferometer to obtain interference fringes. The changes in the number of fringes that crosses the field of view were exploited to calculate the variation in the refractive index with temperature and pressure. Some refractive index-dependent physical constants such as the thermo-optical constant (refractive index temperature coefficient dn/dT), dielectric constant, molar refractivity, and molecular polarizability were calculated for the air at different temperatures and pressure. In the pressure (66–80 cmHg) and temperature (303–338 K) range, the refractive index, dielectric constant, molar refractivity, and molecular polarizability of the air were found to vary between 1.000189 ± 0.000006–1.000281 ± 0.000007, 1.000379 ± 0.000010–1.000562 ± 0.000014, 4.03396 ± 0.13693–4.42908 ± 0.10860 cm3/mol, and 2.01 ± 0.07 × 10–29–2.21 ± 0.05 × 10–29 m3, respectively. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index