SAMOP 2023 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 59: Poster IV
Q 59.46: Poster
Donnerstag, 9. März 2023, 16:30–19:00, Empore Lichthof
The role of frequency stability in measurements of the coefficient of thermal expansion — •Nina Meyer, Tobias Ohlendorf, Uwe Sterr, and Thomas Legero — Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
Materials with small coefficients of thermal expansions (CTEs) of about 10−8 K−1 at room temperature are needed for extreme-ultraviolet lithography, in space and ground-based telescopes or ultra-stable resonators. Those small CTEs are usually accurately measured by two-beam Michelson interferometers [1] or by multiple-beam interference based on Fabry-Pérot resonators [2].
Our approach is based on a Fabry-Pérot resonator, consisting of the test material as spacer and two mirrors in a temperature-controlled vacuum chamber. To measure the small thermal expansion, we stabilize a transfer laser onto the TEM00 mode of the optical resonator and observe the beat frequency of the transfer laser and a frequency standard.
In this poster, we compare the stability of different types of transfer lasers to iodine-stabilized lasers and ultra-stable lasers via a frequency comb and discuss its influence on the CTE accuracy. We also provide an outlook to setups with lasers operating at 1.5 µm wavelength.
[1] R. Schödel, Meas. Sci. Technol. 19, 084003 (2008).
[2] F. Riehle, Meas. Sci. Technol. 9, 1042−1048 (1998).