Tunable Filters

Agile spectral filters with large clear apertures

Liquid crystal tunable spectral filters are gaining wide acceptance in such diverse areas as optical fiber communications, astronomy, remote sensing, pollution monitoring, color generation for display, and medical diagnostics. The large aperture and imaging capability of these devices represent a distinct advantage over conventional dispersive spectral analysis techniques. Furthermore, benefits of liquid crystal tunable filters over acousto-optic tunable filters include low power consumption, low addressing voltage, excellent image quality, and large clear aperture. Unlike conventional filter wheels, liquid crystal tunable filters have no moving parts and are light weight, making them attractive for airborne or remote sensor platforms.

Current efforts at BNS focus on filters exploiting Fabry-Perot effects or polarization interference effects. Applications include tunable notch filters, band selection filters, and multi-spectral/polarization based imaging sensors.