Electrically tunable optical filter for visible wavelength using a liquid crystal multiplexed to a Fabry-Perot etalon

Using the refractive index modulation in liquid crystals by an externally a pplied electric field, we show that a polymer dispersed liquid crystal (PDL C) can be used in a Fabry-Perot etalon to produce a tunable optical filter for use in the visible region. Voltage applied to the film changes the refr active index and the optical length of the cavity, converting the system in to an interference filter with a variable frequency bandwidth. We demonstra te further that the wavelength can be tuned over 150 nm using less than 20 V of power.