Waveguide fabrication in phosphate glasses using femtosecond laser pulses

TLDR

Phosphate glasses exhibit waveguide formation behavior distinct from the widely studied silica system. The study investigates how focused femtosecond laser pulses affect waveguide fabrication in commercial sodium aluminum phosphate glass (Schott IOG‑1). Single‑pass translation of IOG‑1 glass at 20 μm s⁻¹ with 3.5 μJ pulses produces two waveguides on opposite sides of the exposed region, whose positions vary with beam tilt, and fluorescence imaging shows color‑center defects in the exposed area but not within the waveguides.

Abstract

We report on the response of glass to focused femtosecond (fs) laser pulses during waveguide fabrication in a commercial sodium aluminum phosphate glass (Schott IOG-1). Single-pass longitudinal translation of IOG-1 glass with respect to the focused laser beam at a rate of 20 μm/s and pulse energies of 3.5 μJ results in the formation of two waveguides located on opposite sides of the laser-exposed region, which itself does not guide light. This behavior is different from that of the more widely studied silica glass system. The precise location of the waveguides in IOG-1 glass depends on the relative tilt of the fs laser beam with respect to the sample translation direction. Fluorescence imaging of the modified glass using a confocal microscope setup reveals the formation of color center defects in the exposed region but not within the waveguides.