Optically controlled imaging phase mask element
AssigneeBrown University Research Foundation
InventorNabil M. Lawandy
Life of this patent
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Abstract
An optical element includes a phase mask made of a nonlinear material. The element uses the nonlinearity to produce an intensity dependent lens which controls the imaging properties. The invention enables the optical control of the image of an array produced by a diffractive spot generator in direct contact with a thin semiconductor doped glass substrate. By example, the focus of an image at 632.8 nm from a He-Ne laser is controlled by 514.5 nm light from an Argon Ion laser.
Claims20
An optical element, comprising:
- a diffractive phase shift mask for propagating therethrough an optical beam having an intensity;
- and
- a substrate optically coupled to said diffractive phase shift mask, said substrate having an intensity dependent nonlinearity that is manifested at least by a change in an index of refraction of said substrate.
A method for projecting an image upon a surface, comprising the steps of:
- providing a diffractive phase shift mask having features for defining the image, the diffractive phase shift mask being optically coupled to a substrate having an intensity-dependent nonlinearity;
- propagating an optical beam through the diffractive phase shift mask, through the substrate, and onto the surface, the propagating optical beam heating the substrate and inducing a thermal lens in the substrate;
- and
- changing an intensity of the optical beam so as to change a focal length of the thermal lens relative to the surface.
A method for projecting an image upon a surface, comprising the steps of:
- providing a diffractive phase shift mask having features for defining the image, the diffractive phase shift mask being optically coupled to a substrate having an intensity-dependent nonlinearity;
- and
- propagating an optical beam through the diffractive phase shift mask, through the substrate, and onto the surface, the propagating optical beam having an intensity selected for inducing the nonlinearity in the substrate for at least one of varying a focus of the image on the surface or varying a position of the image on the surface.
Dependencies are inferred from the claim text.