3-DIMENSIONAL MICROSCOPIC CRYSTALLIZATION IN PHOTOSENSITIVE GLASS BY FEMTOSECOND LASER-PULSES AT NONRESONANT WAVELENGTH

We investigated three-dimensional microscopic crystallization by irrad iation of femtosecond and nanosecond laser pulses at a nonresonant wav elength of 630 nm in a photosensitive glass containing Ag+ and Ce3+. T he pulse widths of the lasers were 150 fs and 3 ns, respectively. By f ocusing the femtosecond laser beam and following hear-treatment, spot crystallization within the glass of about 10 mu m successfully occurre d without surface crystallization, while the use of the nanosecond las er beam produced no crystallization. By using the femtosecond laser, i t is possible to create three-dimensional structured crystallization b ecause of the use of transparent light and the presence of a threshold for crystallization.