title: Fabrication of a periodic structure with a high refractive-index difference by femtosecond laser pulses.
abstract: A microfabrication process using ultrafast laser pulses in glass was investigated. We investigated the formation of semiconductors by the irradiation of glasses with femtosecond laser pulses. ZnS- or PbS-doped SiO(2)-Al2O(3)-B(2)O(3)-CaO-ZnO-Na(2)O-K(2)O glasses were prepared by a melting method and irradiated by femtosecond laser pulses. Periodic structures in the sample glasses with a high refractive index difference were produced by femtosecond laser pulses. The maximum relative refractive index difference between the irradiated area and the nonirradiated areas was 20%. Diffraction gratings were also fabricated inside the ZnS- or PbS-doped silicate glasses. The diffraction efficiency of these gratings was approximately 90% in the infrared region.
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Takeshima
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kuroiwa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Narita
authors.forename: Shuhei
authors.initials: S
authors.lastname: Tanaka
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Hirao