@article{13421,
  author = {C Ma and J. Yu and T. Legero and Sofia Herbers and Daniele Nicolodi and M. Kempkes and F. Riehle and D. Kedar and J. Robinson and Jun Ye and U. Sterr},
  title = {Ultrastable lasers: investigations of crystalline mirrors and closed cycle cooling at 124 K},
  abstract = {<p>We have investigated crystalline AlGaAs/GaAs optical coatings with three ultra-stable cavities operating at 4 K, 16 K, 124 K and 297 K. The response of the resonance frequencies of cavities to variations in optical power indicates effects beyond the photo-thermo-optic effect observed in dielectric coatings. These effects are strongly dependent on the intensity of the intracavity light at 1.5~\textmu m. When the rear side of the mirrors is illuminated with external light, we observe a prominent photo-modified birefringence for photon energies above the GaAs bandgap, which points to a possible mechanism relating our observations to the semiconductor properties of the coatings. Separately, we also present a low maintenance evolution of our 124 K silicon cavity system where the liquid nitrogen based cooling system is replaced with closed cycle cooling from a pulse-tube cryo-cooler.</p>
},
  year = {2024},
  journal = {Submitted},
  url = {https://arxiv.org/abs/2404.02647},
}