Waveguide grating mirror in a fully suspended 10 meter Fabry-Perot cavity
Abstract
We report on the first demonstration of a fully suspended 10m Fabry-Perot cavity incorporating a waveguide grating as the coupling mirror. The cavity was kept on resonance by reading out the length fluctuations via the Pound-Drever-Hall method and employing feedback to the laser frequency. From the achieved finesse of 790 the grating reflectivity was determined to exceed 99.2% at the laser wavelength of 1064\,nm, which is in good agreement with rigorous simulations. Our waveguide grating design was based on tantala and fused silica and included a ~20nm thin etch stop layer made of Al2O3 that allowed us to define the grating depth accurately during the fabrication process. Demonstrating stable operation of a waveguide grating featuring high reflectivity in a suspended low-noise cavity, our work paves the way for the potential application of waveguide gratings as mirrors in high-precision interferometry, for instance in future gravitational wave observatories.
Cite
@article{arxiv.1104.2780,
title = {Waveguide grating mirror in a fully suspended 10 meter Fabry-Perot cavity},
author = {Daniel Friedrich and Bryan W. Barr and Frank Brückner and Stefan Hild and John Nelson and John Mcarthur and Michael V. Plissi and Matthew P. Edgar and Sabina H. Huttner and Borja Sorazu and Stefanie Kroker and Michael Britzger and Ernst-Bernhard Kley and Karsten Danzmann and Andreas Tünnermann and Ken A. Strain and Roman Schnabel},
journal= {arXiv preprint arXiv:1104.2780},
year = {2015}
}