A Continuously Tunable Optical Filter System in Broad Spectral Range

Abstract

Optical notch and band pass filter systems with continuous fine tuning resolution are realized by combining left- and right-handed cholesteric liquid crystal wedge cells. Notch filter system is polarization-independent in whole spectral range, from similar to 460 nm to similar to 1,000 nm. In the band pass filter system, depending on the arrangement of the cells, it could be either polarization-independent or polarization-dependent. Furthermore, the photonic band gap width of the band pass filter could be changed reversibly from 36 nm to 16 nm.