Optical attenuator
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorJoshua Lentz
Life of this patent
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Abstract
A device includes a number of grating stages having a liquid crystal layer disposed between at least two substrates, where at least one is coated with a photo-alignment layer and transparent electrodes. Each grating stage may be switchably responsive to a voltage, with grating periods of each grating stage selected such that, when the voltage is applied to a grating stage and a laser beam is passed therethrough, optical energy from the laser beam in plus and minus first orders is deflected toward sides of the grating stage and optical energy from a zero order of the laser beam is allowed to pass through the grating stage. A polarization state of the laser beam may be maintained from an input through an output. Each grating stage may include a thickness selected to achromatize the laser beam through the grating stages.
Claims19
A device, comprising:
- a plurality of grating stages arranged for passing a laser beam therethrough, each grating stage in the number of grating stages comprising:
- a first substrate and a second substrate, where one or more of the first substrate and the second substrate is coated with a photo-alignment layer and transparent electrodes;
- a liquid crystal layer disposed between the first substrate and the second substrate and adjacent to the photo-alignment layer, where each grating stage is switchable responsive to a voltage, with grating periods of each grating stage selected such that, when the voltage is applied to a grating stage and the laser beam is passed therethrough, optical energy from the laser beam in plus and minus first orders is deflected toward sides of the grating stage and optical energy from a zero order of the laser beam is allowed to pass through the grating stage, with a polarization state of the laser beam maintained from an input of the laser beam entering the grating stage through an output of the laser beam exiting the grating stage;
- and
- a thickness selected to achromatize the laser beam through the plurality of grating stages.
A method, comprising:
- receiving a laser beam at an input of a plurality of grating stages arranged in a series and being configured to accept a voltage, each grating stage in the plurality of grating stages comprising a liquid crystal layer disposed between a first substrate and a second substrate, where one or more of the first substrate and the second substrate is coated with a photo-alignment layer adjacent to the liquid crystal layer;
- applying a voltage to each grating stage as the laser beam passes through the plurality of grating stages;
- while the voltage is applied at each stage, deflecting optical energy from the laser beam in plus and minus first orders toward a side of each grating stage;
- while the voltage is applied at each stage, allowing optical energy from a zero order of the laser beam to pass through each grating stage;
- and
- while the voltage is applied at each stage, maintaining a polarization state of the laser beam from the input of the number of grating stages to an output of the number of grating stages, where the laser beam is achromatized when passing through the number of grating stages.
Dependencies are inferred from the claim text.