Tunable thermal diffusion and heat accumulation in transparent materials based on varying the scanning speed of a femtosecond laser

Abstract

Based on heat accumulation effects, symmetric optical waveguides in glass can be obtained via femtosecond laser irradiation. Such modification inside glass is interesting in terms of developing integrated mini-optical devices with 3-D structures and micro channels for biosensors. This work experimentally investigated the formation of micro-channels inside porous glass irradiated with an 800 nm, 100 fs, and 250 kHz femtosecond laser with scanning speeds ranging from 250 μm/s to 1000 μm/s at a fixed power of 300 mW. Strong heat accumulation effects were thus observed at laser scanning at 250μm/s, which offered significant variations in structure morphology.