Binary high-efficiency single order gratings for beam switching

Grating structures with a grating period in the range of the illumination wavelength differ in their diffraction properties considerably from conventional diffraction structures. In this case diffraction properties are sensitive in a complex manner to illumination direction, structure thickness, illumination wavelength or polarization. For modeling of the diffraction properties rigorous solutions of the wave have to be used [1]. Specific examples of the properties of such gratings include highly efficient single order gratings or polarization dependent beam splitting structures [2]. Although theoretical modeling of such gratings is known for a long time, practical realization of such gratings was limited until recently by the structuring technology. After first investigations based on an interferometric technique now also more flexible techniques based on direct e-beam writing in the submicrometer range become available [3]. In the following we want to describe at first results for the design of an efficient single order binary phase grating structure. Then the combination of two single order gratings for achieving beam switching properties with small mechanical shifts in the sub micrometer range will be discussed.