Infrared LiF ridge waveguide fabricated by carbon ion irradiation

We report on the fabrication of an optical ridge waveguide in lithium fluoride crystal using the method of C5+ ion irradiation with precise diamond blade dicing. The guiding properties of the waveguide at the infrared wavelengths of 1064 nm, 2200 nm and 4000 nm are investigated in detail. All the near-field modal profiles exhibit single-mode guidance and the minimum propagation losses of the ridge waveguide after annealing are reduced to 0.7 dB cm(-1) (lambda = 1064 nm), 0.4 dB cm(-1) (lambda = 2200 nm) and 0.2 dB cm(-1) (lambda = 4000 nm), respectively. The Raman spectroscopy of the waveguide shows that the ion irradiation does not obviously change the lattice structure of the crystal.