Frequency filters and planar lenses for the terahertz band: Configurations with low- and high-aspect microstructures

We overview the results of experimental development of high-performance frequency filtering and beam focusing devices operating at subterahertz and terahertz frequencies. The quasi-optical band-pass and high-pass filters, as well as planar lenses implemented as subwavelength metallized microstructures with thickness both of the order and much smaller than the wavelength are described. The techniques for fabricating these low- and high-aspect structures using lithographic and laser micromachining technologies are considered.