Encapsulated subwavelength grating as a quasi-monolithic resonant reflector.
For a variety of laser interferometric experiments, the thermal noise of high-reflectivity multilayer dielectric coatings limits the measurement sensitivity. Recently, monolithic high-reflection waveguide mirrors with nanostructured surfaces have been proposed to reduce the thermal noise in interferometric measurements. Drawbacks of this approach are a highly complicated fabrication process and the high susceptibility of the nanostructured surfaces to damage and pollution. Here, we propose and demonstrate a novel quasi-monolithic resonant surface reflector that also avoids the thick dielectric stack of conventional mirrors but has a flat and robust surface. Our reflector is an encapsulated subwavelength grating that is based on silicon. We measured a high reflectivity of 93% for a wavelength of lambda = 1.55 microm under normal incidence. Perfect reflectivities are possible in theory.
Brückner
Frank
F
Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany. roman.schnabel@aei.mpg.de
Friedrich
Daniel
D
Britzger
Michael
M
Clausnitzer
Tina
T
Burmeister
Oliver
O
Kley
Ernst-Bernhard
EB
Danzmann
Karsten
K
Tünnermann
Andreas
A
Schnabel
Roman
R
D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D008027:Light; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation