title: Inscription of optical waveguides in crystalline silicon by mid-infrared femtosecond laser pulses.
abstract: For the first time to the authors' knowledge, optical waveguides have been inscribed in bulk crystalline silicon by ultrafast laser radiation. Femtosecond laser pulses of 40-nm spectral bandwidth, 1-kHz repetition rate, and 1.7-microJ on-target energy were applied at a mid-infrared wavelength of 2.4 microm to induce nonlinear absorption in the focal volume of the beam. By scanning the laser beam with respect to the sample, buried optical waveguides have been created that were single mode at 1550 and 1320 nm and guided light only with its polarization perpendicular to the sample's surface. Propagation losses with an upper limit of 1.2 dB/cm or less were observed throughout the optical telecommunications band.
authors.affiliation: Photonics Group, Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada. amir.nejadmalayeri@utoronto.ca
authors.forename: Amir H
authors.initials: AH
authors.lastname: Nejadmalayeri
authors.forename: Peter R
authors.initials: PR
authors.lastname: Herman
authors.forename: Jonas
authors.initials: J
authors.lastname: Burghoff
authors.forename: Matthias
authors.initials: M
authors.lastname: Will
authors.forename: Stefan
authors.initials: S
authors.lastname: Nolte
authors.forename: Andreas
authors.initials: A
authors.lastname: Tünnermann