Soliton generation in CaF$_2$ crystalline whispering gallery mode resonators with negative thermal-optical effects
Abstract
Calcium fluoride (CaF) crystalline whispering gallery mode resonators (WGMRs) exhibit ultrahigh intrinsic quality factors and a low power anomalous dispersion in the communication and mid-infrared bands, making them attractive platforms for microresonator-based comb generation. However, their unique negative thermo-optic effects pose challenges when achieving thermal equilibrium. To our knowledge, our experiments serve as the first demonstration of soliton microcombs in Q > 109 CaF WGMRs. We observed soliton mode-locking and bidirectional switching of soliton numbers caused by the negative thermo-optic effects. Additionally, various soliton formation dynamics are shown, including breathing and vibrational solitons, which can be attributed to thermo-photomechanical oscillations. Thus, our results enrich the soliton generation platform and provide a reference for generating solitons from WGMRs that comprise other materials with negative thermo-optic effects. In the future, the ultrahigh quality factor of CaF crystal cavities may enable the generation of sub-milliwatt-level broad-spectrum soliton combs.
Keywords
Cite
@article{arxiv.2306.02128,
title = {Soliton generation in CaF$_2$ crystalline whispering gallery mode resonators with negative thermal-optical effects},
author = {Mingfei Qu and Chenhong Li and Kangqi Liu and Weihang Zhu and Yuan Wei and Pengfei Wang and Songbai Kang},
journal= {arXiv preprint arXiv:2306.02128},
year = {2023}
}
Comments
4 pages,5 pictures,description of soliton generation in a calcium fluoride whisper gallery mode microresonators with negative thermo-optical effect,ready for publication in optics letter