Microwave liquid crystal wavelength selector

The combined use of a zero-order grating with liquid crystals to control mi crowaves is presented. A nematic liquid crystal is aligned in the 75 mum ga ps of a grating comprised of 1-mm-thick aluminum slats. A set of resonant t ransmission frequencies is recorded for microwaves incident on this structu re with their electric field perpendicular to the slats. These resonances a re due to the excitation of coupled surface plasmons. A voltage applied bet ween adjacent pairs of slats causes the liquid crystal to realign, allowing sensitive control of the transmitted microwave frequencies. (C) 2001 Ameri can Institute of Physics.