Cascaded Raman lasing in a lithium tetraborate (LB4) whispering gallery mode resonator
Abstract
Lithium tetraborate (LB4) is a lithium borate compound and recently has shown renewed interest due to its exceptional linear and nonlinear optical properties. Its wide transparency range, spanning from 0.16 to 3.5, and low loss in the visible range make LB4 highly popular in applications of harmonics generation and deep ultraviolet radiation. Also, LB4 is a good Raman-active material due to its high Raman gain. Here, a millimeter sized LB4 whispering gallery mode resonator (WGMR) is machined using single point diamond cutting, which has, to the best of our knowledge, the highest reported quality () factor of at 517 nm. Then, stimulated Raman scattering (SRS) was investigated in this LB4 WGMR. When pumped with about 7 mW at 517 nm, four cascaded SRS peaks with wavelengths ranging from 537 nm to 608 nm are demonstrated, which can be clearly observed using an optical grating. Among them, the first order SRS is characterized and has a threshold of 0.69 mW with a slope efficiency of 7.2 %. This is the first implementation of a LB4 whispering gallery mode Raman laser, which will facilitate usages of LB4 WGMR as compact Raman lasing source in future.
Keywords
Cite
@article{arxiv.2411.19131,
title = {Cascaded Raman lasing in a lithium tetraborate (LB4) whispering gallery mode resonator},
author = {Chengcai Tian and Florian Sedlmeir and Jervee Punzalan and Petra Becker and Ladislav Bohatý and Keith C. Gordon and Richard Blaikie and Harald G. L. Schwefel},
journal= {arXiv preprint arXiv:2411.19131},
year = {2024}
}