The refractive index of a gas provides information about the mixing ratios as well as the temperature and pressure at the measurement site. The refractive index becomes practically relevant when a resolution and accuracy of up to the sixth decimal place of this measured quantity can be achieved. This goal is being pursued in the recently launched project “ReSpektIS: Refractive Index Speckle-Tech Integrating Sphere” using a fiber-optic-coupled approach. To this end, fluctuations in the so-called speckle pattern of a laser source are recorded and evaluated as a measure of the change in refractive index at the measurement site. The purely optical system connection also enables potential use in hard-to-reach or potentially explosive environments, as the measurement site and electronic units need only be connected via a single optical fiber. This approach is also intended to facilitate the implementation of decentralized sensor networks.
The research and development work described was funded by the Federal Ministry for Economic Affairs and Energy (BMWE) as part of the research project “Refractive Index Speckle-Tech Integrating Sphere” (ReSpektIS).
Funding code: 49MF250153
