| Abstrakt: |
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 (SrF 2 ) and Nd, Y co-doped calcium fluoride (CaF 2 ) 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:SrF 2 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:SrF 2 , as well as well-preserved Nd fluorescence in the written optical waveguides. |
