Femtosecond Micromachining

 Femtosecond pulse irradiation on a substrate surface induces a formation of sub-micron periodic structures. Such a nano-sized structure will cause modification of mechanical and optical properties of the surface which is useful for manufacturing advanced industrial products.

 Irradiation of the femtosecond laser pulses at low fluence can induce amorphization of crystalline Si. Cross-sectional TEM images of the amorphasized sample (shown left) show the amorphized layer which is quite thin and almost uniform.