Dynamics of permanent structural transformations in ZBLAN induced by self-channeled plasma filament

摘要

The time-resolved dynamics of permanent structural transformations in the ZBLAN (fluoride glass) induced by self-channeled plasma filament were first observed in situ using a high-intensity femtosecond (110 fs) Ti: sapphire laser (λ_p = 800 nm). Self-channeled plasma filament would be induced in ZBLAN glass at the irradiation higher than input intensity of 1.0 x 10~(12) W/cm~2 and photoinduce either the refractive index modification or optical crack modification. At the domain of refractive index modification, the lifetime of induced self-channeled plasma filament was 30 ps and structural transition time for forming the refractive index change was 40 ps. At the domain of optical cracks, however, the lifetime of induced self-channeled plasma filament was 70 ps and structural transition time for forming the optical cracks was 70 ps. A maximum value of refractive index change (Δn) was measured to be 1.3 x 10~(-2). The intensity profile of the output beam transmitted through the refractive index modification showed that the bulk modification produced a permanent structure of optical waveguide.