Dynamic time multiplexing fabrication of holographic polymer dispersed liquid crystals for increased wavelength sensitivity

摘要

Described herein is a new holographic polymer dispersed liquid crystal (HPDLC) medium with broadband reflective properties, and a new technique for fabrication of broadband HPDLC mediums. The new technique involves dynamic variation of the holography setup during HPDLC formation, enabling the broadening of the HPDLC medium's wavelength response. Dynamic variation of the holography setup may include the rotation and/or translation of one or more motorized stages, allowing for time and spatial, or angular, multiplexing through variation of the incident angles of one or more laser beams on a pre-polymer mixture during manufacture. An HPDLC medium manufactured using these techniques exhibits improved optical response by reflecting a broadband spectrum of wavelengths. A new broadband holographic polymer dispersed liquid crystal thin film polymeric mirror stack with electrically-switchable beam steering capability is disclosed.

主权项

1. A holographic polymer dispersed liquid crystal film that reflects a hyperspectral continuum of optical energy within a spectrum of wavelengths, the holographic polymer dispersed liquid crystal film comprising:
a continuous polymer phase comprising an acrylate-containing polymer; and an overlapping liquid crystal layer structure within the continuous polymer phase, the holographic polymer dispersed liquid crystal film exhibiting:
a hyperspectral continuum of peak reflective wavelengths produced by a continuous exposure process exhibiting a uniform reflectance and ranging from a first peak reflective wavelength indicative of a first end of the spectrum to a second peak reflective wavelength greater than the first peak reflective wavelength, the second peak reflective wavelength indicative of a second end of the spectrum, inclusively, wherein:
each and every point of the hyperspectral continuum of peak reflective wavelengths is indicative of a peak reflectance of a respective wavelength of a respective Bragg reflection grating;the hyperspectral continuum of peak reflective wavelengths between the first and second peak reflective wavelengths having a full width at half maximum (FWHM) in a range of from 15 nm to 100 nm or 100 nm or greater;the holographic polymer dispersed liquid crystal film exhibits a scattering intensity less than 1×10−7 dB outside the hyperspectral continuum of peak reflective wavelengths; andthe hyperspectral continuum of peak reflective wavelengths is electrically controllable by switching fields of about 15 to 20 Volts per micrometer at switching times of less than 2 milliseconds;wherein the holographic polymer dispersed liquid crystal film comprises a plurality of reflective gratings within the holographic polymer dispersed liquid crystal film, and at least one of the plurality of reflective gratings is curved.