title: Optical characterization of ultrahigh diffraction efficiency gratings.
abstract: We report on the optical characterization of an ultrahigh diffraction efficiency grating in a first-order Littrow configuration. The apparatus used was an optical cavity built from the grating under investigation and an additional high-reflection mirror. The measurement of the cavity finesse provided precise information about the grating's diffraction efficiency and its optical loss. We measured a finesse of 1580 from which we deduced a diffraction efficiency of (99.635+/-0.016)% and an overall optical loss due to scattering and absorption of just 0.185%. Such high-quality gratings, including the tool used for their characterization, might apply for future gravitational wave detectors. For example, the demonstrated cavity itself presents an all-reflective, low-loss Fabry-Perot resonator that might replace conventional arm cavities in advanced high-power Michelson interferometers.
authors.affiliation: Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Germany. alexander.bunkowski@aei.mpg.de
authors.forename: A
authors.initials: A
authors.lastname: Bunkowski
authors.forename: O
authors.initials: O
authors.lastname: Burmeister
authors.forename: T
authors.initials: T
authors.lastname: Clausnitzer
authors.forename: E-B
authors.initials: EB
authors.lastname: Kley
authors.forename: A
authors.initials: A
authors.lastname: Tünnermann
authors.forename: K
authors.initials: K
authors.lastname: Danzmann
authors.forename: R
authors.initials: R
authors.lastname: Schnabel