Measurement: Sensors (Dec 2021)
Preliminary results of KRISS optical pressure standard system
Abstract
As the harmfulness of mercury has recently emerged, the development of a new concept of primary standard that does not use mercury is required in the low vacuum field. Among these new pressure realization methods, recently, theres have been a lot of research teams about a method of measuring the pressure of a medium by using the optical refractive index of the medium. KRISS is also one of these research teams We designed a Fabry–Perot (FP) cavity structure having two channels to calculate an arbitrary pressure by comparing the laser resonance frequency in a vacuum state, which served as a reference pressure, and that in an arbitrary pressure state. Zerodur was used as the material for the cavity. We fabricated a single-mode (SM) He–Ne laser instead of a commercially available laser to modulate the frequency freely and to achieve a single polarization regardless of the quantum number. With our system, the beat frequency was measured to the internal pressure of a cavity. A 1 MHz beat frequency was found to be approximately equal to a pressure of 1 Pa.
