Stable Reference Cavity for Er and Dy MOT Light

by Alexander Patscheider

Abstract:

In this thesis we describe the setup and characterization of a reference cavity for the stabilization of laser light at several wavelengths. On the one hand, the cavity is used to stabilize light used for the magneto-optical trap of erbium and dysprosium atoms. On the other hand, we want to stabilize laser light for Rydberg excitation at a future date of the experiment. Additionally, the thesis covers the generation of the light at 583 nm and 626 nm, corresponding to the transitions in Er and Dy used for the narrow line MOT, respectively. For the generation of the light at 583 nm we use a seed laser emitting at 1166 nm. This light is then coupled into a Raman fiber amplifier and then frequency doubled within a second harmonic generation (SHG) crystal. With a seed power of 25mW, we obtain slightly less than 2W of 583-nm light. For the 626-nm light we use two fiber lasers at 1550 nm and 1050 nm together with two fiber amplifiers and mix the light in a sum frequency generation (SFG) crystal. With a maximal output power of 5W for each fiber laser we obtain more than 2W of light at 626 nm. The light at 626 nm is stabilized with a stable reference cavity. The two mirrors of the cavity and the spacer between them are made of ultra low expansion glass (ULE), which has a measured minimal thermal expansion coefficient at 21.78(5) °C. The locking of the laser light is done with a fiber-coupled electro-optical modulator that modulates sidebands at two different frequencies. While the laser is resonant to the atomic transition, one of these sidebands is shifted to the cavity resonance. The second sidebands are then used to generate the Pound-Drever-Hall error signal for the electronic locking setup.

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Reference:

Stable Reference Cavity for Er and Dy MOT Light,
Alexander Patscheider,
Master’s Thesis, 2017.

Bibtex Entry:

@article{PatscheiderMSc,
 title = {Stable Reference Cavity for Er and Dy MOT Light},
  author = {Patscheider, Alexander},
  journal = {Master's Thesis},
  year = {2017},
  month = {Feb},
  abstract = {In this thesis we describe the setup and characterization of a reference cavity for the
stabilization of laser light at several wavelengths. On the one hand, the cavity is used to
stabilize light used for the magneto-optical trap of erbium and dysprosium atoms. On the
other hand, we want to stabilize laser light for Rydberg excitation at a future date of the
experiment. Additionally, the thesis covers the generation of the light at 583 nm and 626 nm,
corresponding to the transitions in Er and Dy used for the narrow line MOT, respectively.
For the generation of the light at 583 nm we use a seed laser emitting at 1166 nm. This light
is then coupled into a Raman fiber amplifier and then frequency doubled within a second
harmonic generation (SHG) crystal. With a seed power of 25mW, we obtain slightly less
than 2W of 583-nm light. For the 626-nm light we use two fiber lasers at 1550 nm and
1050 nm together with two fiber amplifiers and mix the light in a sum frequency generation
(SFG) crystal. With a maximal output power of 5W for each fiber laser we obtain more
than 2W of light at 626 nm. The light at 626 nm is stabilized with a stable reference cavity.
The two mirrors of the cavity and the spacer between them are made of ultra low expansion
glass (ULE), which has a measured minimal thermal expansion coefficient at 21.78(5) &deg;C.
The locking of the laser light is done with a fiber-coupled electro-optical modulator that
modulates sidebands at two different frequencies. While the laser is resonant to the atomic
transition, one of these sidebands is shifted to the cavity resonance. The second sidebands
are then used to generate the Pound-Drever-Hall error signal for the electronic locking
setup.},
  url = {http://www.erbium.at/FF/wp-content/uploads/2017/05/170109_Alexander_Patscheider_MasterThesis.pdf},
}