Laser Frequency Stabilization by the Pound-Drever-Hall Technique
Chia-Yu Hsu1*, Yu-Chih Tseng1, Ite A. Yu1
1Department of physics, National Tsing Hua University, Hsinchu, Taiwan
* Presenter:Chia-Yu Hsu,
The frequency stabilization of two or more laser fields plays an important role in the researches of electromagnetically induced transparency (EIT), slow light, stored light, and their applications in quantum information manipulation. EIT transitions involving Rydberg states can dramatically increase photon-photon interactions, making the system useful in the studies of quantum information science. However, the injection-lock method cannot work for the stabilization of the sum of two laser frequencies in the ladder-type transition of Rydberg EIT. We aim to lock the frequencies of two laser fields, making the fluctuation of their sum less than 100 kHz, by the Pound-Drever-Hall technique. With that, the decoherence rate in a Rydberg-EIT system can be reduced by two order of magnitude. We have successfully locked a laser by the use of a Fabry-Perot cavity and its frequency fluctuation was around 100 kHz. In the next step, two independent lasers will be frequency locked to two modes of the same optical cavity, whose length is locked to the two-photon resonance frequency of the Rydberg-EIT transition. Our work develops the frequency stabilization technique of lasers with very different colors, which is very useful for the experiments of Rydberg qubits.

Keywords: Pound-Drever-Hall technique, Rydberg EIT