Journal of Radio Electronics. eISSN 1684-1719. 2025. №12

Full text in Russian (pdf)

DOI: https://doi.org/10.30898/1684-1719.2025.12.3

MEASUREMENT OF REFRACTIVE INDEXES OF HYDROGEN,
NITROGEN AND Krypton AT Different pressure values
WITH A FIBER OPTICAL REFRACTOMETER

E.I. Dolzhenko, K.A. Tomyshev, O.V. Butov

Kotelnikov IRE RAS

125009, Russia, Mokhovaya str., 11, b.7

The paper was received October 21, 2025.

Abstract. This paper presents the results of measuring the refractive indices of hydrogen, nitrogen, and krypton at different pressures at a wavelength of ~1350 nm. The measurements were performed using a fiber optical refractometer based on a Bragg grating inscribed with femtosecond laser radiation. The results demonstrated a monotonic increase in the refractive index with increasing gas pressure. A noticeable feature was that the refractive index growth rate was higher for larger molecules. Moreover, the dependence of the refractive index on the pressure value displayed a high degree of linearity The obtained experimental results complement the missing data regarding gases’ refractive indexes in the closer infrared range, as well as confirm viability of using femtosecond fiber Bragg gratings for the purposes of gas refractometry.

Key words: fiber Bragg grating, femtosecond inscription, fiber optical refractometer, gas medium.

Financing: The research was conducted within the framework of Kotelnikov Institute of Radioengineering and Electronics (IRE) Russian Academy of Sciences (RAS) State Task.

Corresponding author: Dolzhenko Egor Igorevich, dolzhenko@phystech.edu

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For citation:

Dolzhenko E.I., Tomyshev K.A., Butov O.V. Measurement of refractive indexes of hydrogen, nitrogen and krypton at different pressure values with a fiber optical refractometer. // Journal of Radio Electronics. – 2025. – №. 12. https://doi.org/10.30898/1684-1719.2025.12.3 (In Russian)