Three-dimensional microscopic crystallization in photosensitive glass by femtosecond laser pulses at nonresonant wavelength

We investigated three-dimensional microscopic crystallization by irradiation of femtosecond and nanosecond laser pulses at a nonresonant wavelength of 630 nm in a photosensitive glass containing Ag+ and Ce3+. The pulse widths of the lasers were 150 fs and 3 ns, respectively. By focusing the femtosecond laser beam and following hear-treatment, spot crystallization within the glass of about 10 mu m successfully occurred without surface crystallization, while the use of the nanosecond laser beam produced no crystallization. By using the femtosecond laser, it is possible to create three-dimensional structured crystallization because of the use of transparent light and the presence of a threshold for crystallization.