Self-fabricated single mode waveguide in fluoride glass excited by self-channeled plasma filaments

摘要

Self-fabricated permanent structure of single mode waveguide in optical fluoride glasses was demonstrated using the self-channeled plasma filament excited by a femtosecond (130 fs) Ti: sapphire laser (λ_p=790 nm). The photoinduced refractive index modification in ZrF_4-BaF_2-LaF_3-AlF_3-NaF glasses reached a length of approximately 10-15 mm from the input surface of the optical glass with the diameters ranging from 5 to 8 μm at the input intensities of more than 1.0×10~(12) W/cm~2. The graded refractive index profiles were fabricated to be a symmetric form from the center of optical fluoride glass, and a maximum value of refractive index change (An) was measured to be 1.3×10~(-2). The beam profile of the output beam transmitted through the modified region showed that the photoinduced refractive index modification produced a permanent structure of single mode waveguide.