Laser based optical interferometer manometer design for primary pressure standard in India

TL;DR

This paper presents the design and theoretical analysis of a laser-based optical interferometer manometer for establishing primary pressure standards in India, emphasizing a mercury-free, environmentally friendly approach based on physical constants.

Contribution

It introduces a novel optical cavity design and an all-fiber setup for primary pressure measurement, advancing pressure metrology without mechanical parts.

Findings

Theoretical calculations for optical cavity parameters.

Design of a dual cavity mechanical system.

Proposed all-fiber optical setup for pressure measurement.

Abstract

The SI unit of pressure, i.e. Pascal is realized with mechanical devices such as ultrasonic interferometer manometers and pressure balances for the pressure range 1 Pa to 100 kPa. Recently, optical interferometer manometers are being used to realize Pascal. Such a realization is mercury-free and environmentally friendly and does not depend on any mechanical motions as in piston gauges and is based on physical constants. It consists of an optical Fabry-Perot cavity as a refractometer and is based on the measurement of the resonant frequency of the cavity using lasers. In this paper, we report the theoretical calculations for such an optical cavity and discuss various parameters for the laser required for developing such a cavity-based refractometer system. We present the mechanical design for the dual cavity and an all-fiber optical set-up to be used for the next generation of primary pressure standards in the barometric region of pressure at CSIR-National physical laboratory, India.