| 摘要 |
A liquid crystal based broadband filter and imaging system for analyzing the polarization state of radiation. The filter includes four elements: a quarter wave plate; a 45° polarization rotator; a 90° polarization rotator; and a fixed polarizer. The first three of these elements are electronically switchable, allowing the user to select from any of the six possible polarization states. The switchable elements use multiple liquid crystal cells made from dual-frequency materials. A dual-frequency signal is used to activate and deactivate the various elements to achieve the desired state configuration. The dual-frequency signal drives the liquid crystal cells in and out of states, improving the overall switching time of the filter. The configuration of the liquid crystal cells within each of the filter allows broadband operation over most of the visible, infrared and ultraviolet spectra. The filter cycles through six configurations corresponding to the six polarization states of the incident radiation. Thus, the polarization state of the radiation can be completely characterized using the four Stokes parameters. Information related to the intensity and polarization of the radiation can be stored, displayed and analyzed.
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