title: All-reflective coupling of two optical cavities with 3-port diffraction gratings.
abstract: The shot-noise limited sensitivity of Michelson-type laser interferometers with Fabry-Perot arm cavities can be increased by the so-called power-recycling technique. In such a scheme the power-recycling cavity is optically coupled with the interferometer's arm cavities. A problem arises because the central coupling mirror transmits a rather high laser power and may show thermal lensing, thermo-refractive noise and photo-thermo-refractive noise. Cryogenic cooling of this mirror is also challenging, and thus thermal noise becomes a general problem. Here, we theoretically investigate an all-reflective coupling scheme of two optical cavities based on a 3-port diffraction grating.We show that power-recycling of a high-finesse arm cavity is possible without transmitting any laser power through a substrate material. The power splitting ratio of the three output ports of the grating is, surprisingly, noncritical.
authors.affiliation: Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik and Leibniz Universität Hannover, Callinstr. 38, 30167 Hannover, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Burmeister
authors.forename: Michael
authors.initials: M
authors.lastname: Britzger
authors.forename: André
authors.initials: A
authors.lastname: Thüring
authors.forename: Daniel
authors.initials: D
authors.lastname: Friedrich
authors.forename: Frank
authors.initials: F
authors.lastname: Brückner
authors.forename: Karsten
authors.initials: K
authors.lastname: Danzmann
authors.forename: Roman
authors.initials: R
authors.lastname: Schnabel