Power-recycled Michelson interferometer with a 50/50 grating beam splitter

We designed and fabricated an all-reflective 50/50 beam splitter based on a dielectric grating. This beam splitter was used to set up a power-recycled Michelson interferometer with a finesse of about FPR ? 880. Aspects of the diffractive beam splitter as well as of the interferometer design are discussed.