| 主权项 |
1. An optical shutter that is rapidly switchable between optical states to alternately transmit visible radiation and near infrared radiation, comprising:
a broadband wavelength selective polarizing filter constructed to impart a polarization state to incident radiation and transmit polarized radiation within at least the visible wavelength region and the near infrared region of the electromagnetic spectrum; a wavelength selective polarizing filter pair including, in optical series arrangement, a wavelength selective polarizing filter transmitting polarized radiation within the visible wavelength region and a wavelength selective polarizing filter transmitting polarized radiation within the near infrared wavelength region; and a liquid crystal polarization modulator positioned to receive incident radiation for internal propagation through the liquid crystal polarization modulator, positioned between the broadband wavelength selective polarizing filter and the wavelength selective polarizing filter pair, and responsive to a first value and a second value of an applied control signal to switch the internally propagating radiation to, respectively, a first polarization state and a second polarization state to produce, in cooperation with the broadband wavelength selective polarizing filter and the wavelength selective polarizing filter pair, optical shutter output radiation in different wavelength regions of the electromagnetic spectrum, the switching of the internally propagating radiation to the first polarization state causing transmission and blockage of the optical shutter output radiation within, respectively, the visible wavelength region and the near infrared region, and the switching of the internally propagating radiation to the second polarization state causing transmission and blockage of the optical shutter output radiation within, respectively, the near infrared wavelength region and the visible wavelength region. |
