Microwave liquid crystal wavelength selector

The combined use of a zero-order grating with liquid crystals to control microwaves is presented. A nematic liquid crystal is aligned in the 75 mum gaps of a grating comprised of 1-mm-thick aluminum slats. A set of resonant transmission frequencies is recorded for microwaves incident on this structure with their electric field perpendicular to the slats. These resonances are due to the excitation of coupled surface plasmons. A voltage applied between adjacent pairs of slats causes the liquid crystal to realign, allowing sensitive control of the transmitted microwave frequencies. (C) 2001 American Institute of Physics.