Optical spot size changer

Claim 2

An optical memory comprising: light source means for producing a light beam, the light beam having a beam waist proximate a first plane, focusing means for forming at a second plane a focused light spot which is essentially an image of the intensity distribution of the light beam at the first plane, a memory medium upon which information is stored, the memory medium being positioned proximate the second plane, a body of material positioned essentially at the first plane, the body having electric field controllable optical properties capable of altering the intensity distribution of the light beam, and electrode means for controllably applying a nonuniform electric field to the body such that a nonuniform change in the intensity distribution of the light beam occurs, thereby causing an effective reduction in the size of the beam waist and the focused light spot.

Claim 3

The invention as described in claim 1 wherein the body is an electro-optic material.

Claim 4

The invention as described in claim 1 wherein the body is an electro-absorptive material.

Claim 5

The invention as described in claim 1 wherein the body comprises a right cylindrical body having a cylindrical surface and first and second faces.

Claim 6

The invention as described in claim 4 wherein the electrode means comprise: a first electrode attached to and extending around the cylindrical surface proximate to the first face, and a second electrode attached to and extending around the cylindrical surface proximatE to the second face.

Claim 7

The invention as described in claim 4 wherein the right cylindrical body is an electro-optic material having the 42m or 43m type of point symmetry and further comprising: polarizer means for providing the light beam with a first polarization direction as it enters the right cylindrical body, and analyzer means positioned between the body and the focusing means for transmitting that portion of the light beam having the first polarization direction.

Claim 8

The invention as described in claim 4 wherein the right cylindrical body is an electro-absorptive material.

Claim 9

The invention as described in claim 1 wherein the body comprises a rectangular parallelepiped having first and second faces and first, second, third and fourth sides.

Claim 10

The invention as described in claim 8 wherein the electrode means comprise electrodes attached to and extending the length of each of the four sides, the electrodes attached to the first and third opposing sides being adapted to have a first potential applied thereto and the electrodes attached to the second and fourth opposing sides adapted to have a second potential applied thereto, thereby establishing a quadrupolar electric field within the body.

Claim 11

The invention as described in claim 9 wherein the body is an electro-optic material having the 3m or 4mm point symmetry, and further comprising: polarizer means for providing the light beam with a first polarization direction as it enters the body, and analyzer means positioned between the body and the focusing means for transmitting that portion of the light beam having the first polarization direction.

Claim 12

The invention as described in claim 8 wherein the body is an electro-absorptive material.

Claim 13

In an optical system having a light source for producing a light beam, a memory medium upon which information is stored, and focusing means for forming a focused light spot at the plane of the memory medium, apparatus for controllably changing the size of the focused light spot, the apparatus comprising: a body of linear electro-optic material positioned between the light source and focusing means, the body having electric field controllable indices of refraction capable of altering the wave front shape of the light beam, electrode means for controllably applying a nonuniform electric field to the body such that a non-uniform change in the wave front shape of the light beam occurs, thereby causing interference of portions of the light beam at the plane of the memory medium and an increase in the size of the focused light spot in a first direction, and beam scanning means for causing relative motion between the light beam and the memory medium in a second direction essentially orthogonal to the first direction.

Claim 14

In an optical system having a light source for producing a light beam, a memory medium upon which information is stored, and focusing means for forming a focused light spot at the plane of the memory medium, apparatus for controllably changing the size of the focused light spot, the apparatus comprising: a body of linear electro-optic material positioned between the light source and focusing means, the body having electric field controllable indices of refraction capable of altering the wave front shape of the light beam, electrode means for controllably applying a nonuniform electric field to the body such that a non-uniform change in the wave front shape of the light beam occurs, thereby causing interference of portions of the light beam at the plane of the memory medium and an increase in the size of the focused light spot in a first direction, and beam scanning means for causing relative motion between the light beam and the memory medium in a second direction essentially orthogonal to the first direction.

Claim 15

The invention as described in claim 12 wherein the body comprises a rectangular parallelepiped of electro-optic material having first and second faces and first, second, third and fourth sides.

Claim 16

The invention as described in claim 13 wherein the electrode means comprises a pair of shaped electrodes adjacent the first and third opposing parallel sides of the body, each of the electrodes comprising a plurality of triangular regions having minimum area at the center of the first and third sides and maximum area near the edges of the first and third sides which border the second and fourth sides.

Claim 17

The invention as described in claim 13 wherein the electrode means comprises: first electrode attached to the first side proximate the first face, second electrode attached to the third side proximate the first face, third electrode attached to the first side proximate the second face, and fourth electrode attached to the third side proximate the second face, the electrodes adapted to have a first potential applied to the first and third electrodes and a second potential applied to the third and fourth electrodes.