标题：Stress-induced optical waveguides written by an ultrafast laser in Nd3+, Y3+ co-doped SrF2 crystals
作者：Babu, B. Hari; Lyu, Chengkun; Billotte, Thomas; Pallares-Aldeiturriaga, D.; Poumellec, Bertrand; Lopez-Higuera, J. M.; Hao, Xiao-Tao; La 更多 作者机构：[Babu, B. Hari; Lyu, Chengkun; Hao, Xiao-Tao] Shandong Univ, Sch Phys, State Key Lab Crystal Mat, Jinan 250100, Shandong, Peoples R China.; [Billott 更多
通讯作者：Hao, XiaoTao;Hao, XT
通讯作者地址：[Hao, XT]Shandong Univ, Sch Phys, State Key Lab Crystal Mat, Jinan 250100, Shandong, Peoples R China.
摘要：In this paper, we report on the ultrafast laser-induced birefringence, refractive index changes, and enhanced photoluminescence properties in the volume of neodymium (Nd), yttrium (Y) co-doped strontium fluoride (SrF2) and Nd, Y co-doped calcium fluoride (CaF2) crystals. The optical waveguides written with 500 kHz repetition rate provided lowest propagation loss of 1.63 +/- 0.21 dB cm(-1) for transverse magnetic (TM) polarization at 632.8 nm in Nd,Y:SrF2 crystal. The measured retardance can be interpreted by stress-induced birefringence related to the permanent volume expansion, photo induced by a non-spherical irradiated zone. The absorption, steady-state, and time-resolved photoluminescence properties are also carried out in and out of the laser irradiated zone, enabling the local changes of the Nd and Y network in Nd,Y:SrF2, as well as well-preserved Nd fluorescence in the written optical waveguides. (C) 2019 Optical Society of America