Ability of gas modulation to reduce he pickup of drifts in refractometry

Gas modulation refractometry (GAMOR) is a methodology for assessment of gas refractivity, molar density, and pressure that, by a rapid gas modulation, exhibits a reduced susceptibility to various types of disturbances. Although previously demonstrated experimentally, no detailed analysis of its ability to reduce the pickup of drifts has yet been given. This work provides an explication of to what extent modulated refractometry in general, and GAMOR in particular, can reduce drifts, predominantly those of the cavity lengths, gas leakages, and outgassing. It is indicated that the methodology is insensitive to the linear parts of so-called campaign-persistent drifts and that it has a significantly reduced susceptibility to others. This makes the methodology suitable for high-accuracy assessments and out-of-laboratory applications. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.

Automated summary

Gas modulation refractometry (GAMOR) is a methodology that reduces susceptibility to disturbances by rapidly modulating gas, particularly effective in reducing drifts related to cavity lengths, gas leakages, and outgassing. It is insensitive to linear parts of certain drifts and significantly less susceptible to others, making it suitable for high-precision assessments and applications outside of the laboratory.