Our reflectometer GLACIER uses the extreme sensitivity of cavity ring-down spectroscopy to quantify the losses of advanced optical coatings down to 5 ppm. As a typical application the device can characterize supra-mirrors with up to 99.9995 % reflectivity. Conventional absorption and reflection measurements are not sufficiently sensitive to quantify today´s super-reflective mirror coatings and are typically limited to the > 1000 ppm range (corresponding to < 99.9 % reflectivity). Cavity ring-down spectroscopy measures optical losses by the decay of the energy stored inside a cavity. The technique reaches unrivalled sensitivity, because losses are experienced with each round trip inside the cavity over and over again. Smaller losses lead to longer intra-cavity dwell time thereby automatically increasing measurement precision. The device features high-speed data acquisition and allows to record measurements within seconds. It is delivered complete with a computer and a user-friendly software interface for acquisition and real-time analysis.
Key Product Features
- Reflectivity measurements up to 99.9995%
- Continuous angles of incidence (0°-45°)
- S and p polarization (separately)
- Antireflective coating characterization down to 0.0005% (5 ppm)
- Simple and reproducible alignment
- Spring-loaded mirror fixtures for reproducible mounting without strain
- Computer and user-friendly software interface included
- High-speed data acquisition and real-time analysis
- Wavelengths in the range 375-1550 nm available
- Footprint 85 x 45 cm²
The figure above shows a typical GLACIER measurement of an ultrahigh-reflective mirror for 1030 nm. The losses of the test mirror were obtained by subtracting the results of a reference measurement with an empty cavity. Therefore, an absolute measurement of the test mirror is realized.