Publications
Broadband Reflectance and Transmittance Characterization of Crystalline Supermirrors
- Author(s)
- Lukas Perner
- Abstract
The thesis at hand describes reflectance R and transmittance T measurements per-formed on a pair of substrate-transferred crystalline supermirrors centered at a wavelength of 4.54 μm. For this purpose, two low-cost, flexible and spectrally broadband measurement setups were built. For the reflectance measurements, a cavity ring-down scheme, using a Fabry-Pérot quantum cascade laser, was implemented. This setup exploited direct passive feedback effects of the measurement cavity on the source laser in a simple linear configuration. The transmittance was determined using a direct approach, comparing the intensity of both, the light incident on and the transmitted by the mirror coating; using a globar type white light source for power stability and lock-in detection to enhance the signal-to-noise ratio and dynamic range. In both setups, a reflection-grating monochromator was used to achieve spectrally resolved measurements. We measured a maximum reflectance R=(0.9998215−(33)+(31)), and minimum transmittance T=(142±15) ppm. Since R+T+l=1, this allowed for an estimation of residual loss (absorption and scatter) in the order of l=(37±18) ppm. Alongside these measurement results, the needed theoretical basics and models are derived and explained.
- Organisation(s)
- Faculty Center for Nano Structure Research
- No. of pages
- 63
- DOI
- https://doi.org/10.25365/thesis.57435
- Publication date
- 04-2019
- Austrian Fields of Science 2012
- 103016 Laser physics, 103008 Experimental physics, 103021 Optics, 104026 Spectroscopy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/b3d24243-7f98-4c48-bed4-4f68ae1840d1