Multispectral imaging with a liquid crystal tunable filter

We report on a new class of instrument for imaging spectral analysis, the tunable liquid crystal filter (LCTF). The LCTF is an optical filter, similar to an interference filter, whose center wavelength is electronically tunable with no moving parts, in a few milliseconds, across hundreds of nanometers. The filter is a polarization interference filter based on the Lyot design, using the electro-optic action of liquid crystals to tune the passband. Imaging quality is near the diffraction limit and there is no image shift as the filter is tuned. Bandwidths ranging from a 0.25 nm to 60 nm have been achieved, for use in high-resolution sequential RGB imaging, microscopy of multiply-tagged fluorescent samples, bathymetry, and remote sensing. LCTFs are presently being applied to agricultural quality control measurements.

[1]  Stephen D. Jacobs,et al.  Liquid-crystal laser optics: design, fabrication, and performance , 1988 .

[2]  Anna M. Lackner,et al.  Near Ultraviolet Photostability of Liquid Crystal Mixtures , 1986 .

[3]  Peter J. Miller,et al.  Tunable narrowband birefringent filters for astronomical imaging , 1990, Astronomical Telescopes and Instrumentation.

[4]  M. Schadt,et al.  Voltage-Dependent Optical Activity of a Twisted Nematic Liquid Crystal , 1971 .

[5]  M. J. Bradshaw,et al.  Liquid crystal devices , 1983 .

[6]  Rudolf Oldenbourg,et al.  Fast imaging polarimetry with precision universal compensator , 1994, Optics & Photonics.

[7]  J M Beckers,et al.  Observing the sun with a fully tunable Lyot-Ohman filter. , 1975, Applied optics.

[8]  J. S. Sweeney,et al.  A laser heating system that stabilizes and controls the temperature : diamond anvil cell applications , 1991 .

[9]  Thomas G. Chrien,et al.  Imaging spectrometer using a liquid crystal tunable filter , 1993, Defense, Security, and Sensing.

[10]  A. M. Title,et al.  Tunable Birefringent Networks , 1980, Optics & Photonics.

[11]  P. Miller,et al.  Use of tunable liquid crystal filters to link radiometric and photometric standards , 1991 .

[12]  Peter J. Miller,et al.  Liquid crystal tunable light filters for surveillance and remote sensing applications , 1993, Defense, Security, and Sensing.

[13]  S T Wu.  Design of a liquid crystal based tunable electrooptic filter. , 1989, Applied optics.

[14]  L. Blinov.  Electro-optical and Magneto-optical Properties of Liquid Crystals , 1983 .

[15]  H. A. Tarry.  Electrically tunable narrowband optical filter , 1975 .

[16]  Greg A. Kopp,et al.  Tunable birefringent filters using liquid crystal variable retarders , 1996, Other Conferences.

[17]  J. Staromlynska.  A double-element broad-band liquid crystal tunable filter-factors affecting contrast ratio , 1992 .

[18]  Kristina M. Johnson,et al.  Smectic liquid crystal tunable filters , 1991 .

[19]  Russell A. Chipman,et al.  Polarization characterization of an LCTV with a Mueller matrix imaging polarimeter , 1993, Defense, Security, and Sensing.

[20]  Tien-Hsin Chao,et al.  Acousto-optic tunable filter imaging spectrometer for NASA applications: breadboard demonstration , 1990, Optics & Photonics.

[21]  K C Lim,et al.  Absorption and scattering measurements of nematic liquid crystals. , 1987, Applied optics.