Hannover 2020 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 22: Posters: Quantum Optics and Photonics II
Q 22.1: Poster
Dienstag, 10. März 2020, 16:30–18:30, Empore Lichthof
Systematic investigations of a 633-nm iodine stabilized diode laser utilizing NICE-OHMS — •Florian Krause, Erik Benkler, and Uwe Sterr — Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
The wavelength 633 nm is common for interferometry and metrology and helium-neon lasers are the prevalent source. Nevertheless, another laser technique is needed, because the technical know-how for building and maintaining helium-neon lasers is vanishing. Iodine stabilized diode lasers at 633 nm using the Noise-Immune Cavity-Enhanced Optical Heterodyne Spectroscopy (NICE-OHMS) technique are promising candidates for an alternative practical realization of the meter.
An extended-cavity diode laser (ECDL) is stabilized to hyperfine lines of 127I2. At an averaging time of 1 s this system reaches a short-term frequency instability of 2.4×10−12, which is better than an iodine stabilized helium-neon laser. However, long-term environmental influences disturb the frequency. Systematic investigations of these influences on the absolute frequency were carried out to enable further improvement of the stability. For example the sensitivity on the mismatch between NICE-OHMS modulation frequency fmod and the Free Spectral Range (FSR) fFSR of the cavity was examined. To avoid this mismatch, the modulation frequency fmod is actively locked to the FSR.
For comparison NICE-OHMS signals were simulated, considering the special structure of the iodine spectrum, which consists many overlapping Doppler-broadened hyperfine lines.