Cladding waveguides are fabricated in Yb,Na:CaF2 crystal by applying femtosecond laser inscription. Waveguide properties are investigated in terms of guiding behaviors and confocal micro-Raman characterizations. In addition, under 946 nm excitation, visible cooperative up-conversion emissions at 478 nm induced by Yb3+ ion pairs are observed while other visible bands are detected owing to the impurities of Er3+ and Tm3+ ions.
Zhang, L., Guo, T., Ren, Y., Cai, Y., Mackenzie, M. D., Kar, A. K., & Yao, Y. (2019). Cooperative up-converted luminescence in Yb,Na:CaF2 cladding waveguides by femtosecond laser inscription. Optics Communications, 441, 8-13. https://doi.org/10.1016/j.optcom.2019.01.032