飞秒激光写入Nd:CaF2晶体制备表面包层光波导

We report on the superficial cladding waveguides fabricated by direct femtosecond laser writing in Nd:CaF2 crystal with three different group of parameters. The lowest propagation loss of waveguides has been determined to be 0.7 dB/cm at wavelength of 632.8 nm along TE polarization. The near fundamental modal distributions have been imaged through the end-face coupling technique. The guidance of the waveguides is found to possess low sensitivity on polarization of the probe light. By using a confocal microscope system, the micro-fluorescence spectra are also obtained, which indicates the photoluminescence features of the Nd3+ ions are well preserved in the waveguide cores after direct femtosecond laser writing.