Binary diffraction gratings for controlling polarization and phase of laser light [review]

Components of thin microoptics with nanostructured surface for polarization and phase control are investigated. These components include transmitting or reflecting subwavelength diffraction gratings that have space-variant direction and filling factor, but near-uniform period and depth of the relief, whose features can vary in size from dozens to hundreds of nanometers for the visible wavelength range. The sectoral diffractive polarizers with a small number of sectors, which transform linear polarization into radial or azimuthal polarization, and subwavelength binary microlenses for tight focusing of laser light are investigated in detail. Examples of specific micropolarizers and metalenses manufactured in amorphous silicon films are given.