title: Ultralow-threshold Yb(3+):SiO(2) glass laser fabricated by the solgel process.
abstract: A Yb-doped silica microcavity laser on a silicon chip is fabricated from a solgel thin film. The high-Q micro-toroid cavity, which has a finesse of 10,000, is evanescently coupled to an optical fiber taper. We report a threshold of 1.8 microW absorbed power that is, to the best of our knowledge, the lowest published threshold to date for any Yb-doped laser. The effect of Yb(3+) concentration on laser threshold is experimentally quantified.
authors.affiliation: Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA. ostby@caltech.edu
authors.forename: Eric P
authors.initials: EP
authors.lastname: Ostby
authors.forename: Lan
authors.initials: L
authors.lastname: Yang
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Vahala