Interferometry with nano-structured optics

We research and develop nano-structured diffraction gratings to split and recombine laser beams in advanced gravitational wave detectors. These all-reflective components can replace the partly transmissive mirrors used in today's detectors. The sensitivity limiting problem of heat absorption in transmissive elements can be solved with this technology.

A new low-loss interferometer concept was demonstrated with custom fabricated gratings [1]. Optimization of the grating design and improvements of the lithographic manufacturing process led to gratings with unprecedented optical quality. A world record diffraction efficiency of 99.62 % has been achieved [2] (2006). Meanwhile a reflectivity of even 99,8% has been achieved [3].

Bibliography:
[1] A. Bunkowski, O. Burmeister, P. Beyersdorf, K. Danzmann, and R. Schnabel, T. Clausnitzer, E.-B. Kley, A. Tünnermann; "Low-loss grating for coupling to a high-finesse cavity", Optics Lett. 29, 2342 (2004).
[2] A. Bunkowski, O. Burmeister, T. Clausnitzer, E.-B. Kley, A. Tünnermann, K. Danzmann, R. Schnabel; "Optical Characterization of ultra-high efficiency gratings", Appl. Opt. 45, 5795 (2006).
[3] F. Brückner, D. Friedrich, T. Clausnitzer, M. Britzger, O. Burmeister, K. Danzmann, E.-B-. Kley, A. Tünnermann, R. Schnabel; "Realization of a Monolithic High-Reflectivity Cavity Mirror from a Single Silicon Crystal", Phys. Rev. Lett. 104, 163903 (2010)

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