Subwavelength gratings for polarization conversion and focusing of laser light

We review thin micro-optics components with nanostructured microreliefs intended to control the polarization and phase of laser light. These components include transmission and reflection subwavelength diffraction gratings characterized by spatially −varying groove directions and fill factors, with the microrelief period and depth remaining approximately unchanged. In the visible spectrum, the microrelief features may vary in size from dozens to hundreds of nanometers. Segmented diffractive micropolarizers for linear to radial/azimuthal polarization conversion and subwavelength microlenses for tightly focusing the laser light are discussed in detail. Examples of particular micropolarizers and microlenses fabricated in amorphous silicon films are also given.