Micromachining bulk glass by use of femtosecond laser pulses with nanojoule energy

Abstract:

Using tightly-focused femtosecond laser pulses of just 5 nJ we produce optical breakdown and structural change in bulk transparent materials, and demonstrate micromachining of transparent materials using unamplified lasers. We present measurements of the threshold for structural change in Corning 0211 glass, as well as a study of the morphology of the structures produced by single and multiple laser pulses. At high repetition-rate, multiple pulses produce a structural change dominated by cumulative heating of the material by successive laser pulses. Using this cumulative heating effect, we write single-mode optical waveguides inside bulk glass using only a laser oscillator.