Increased Bragg angle sensitivity hologram system and method

Claim 2

A hologram system comprising: a first volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 1 relative to an exterior planar surface of the first volume hologram, and each Bragg plane spaced a distance L 1 apart; a second volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 2 relative to an exterior planar surface of the second volume hologram, and each Bragg plane spaced a distance L 2 apart, Φ 2 being equal to Φ 1 and L 2 being equal to L 1 , the second volume hologram oriented with its Bragg planes parallel with the Bragg planes of the first volume holograms; and a means for optically coupling the first and second volume holograms.

Claim 3

The system of claim 1, wherein the first and second volume holograms have the same thickness.

Claim 4

The system of claim 1, wherein the combined thickness of the first and second volume holograms is T, where T≧25 microns.

Claim 5

The system of claim 1, further including a first and a second substrate in supporting relationship to the first and second holograms, respectively, the first and second substrates located on opposite sides of the first and second volume holograms.

Claim 6

The system of claim 1, wherein the optical coupling means is a radiation cured cement.

Claim 7

The system of claim 1, wherein the first and second volume holograms are made from separate pieces of a single volume hologram.

Claim 8

The system of claim 1, wherein the first and second volume holograms are made of dichromated gelatin.

Claim 9

The system of claim 1, wherein the first and second volume holograms comprise a hologram assembly, the hologram assembly for receiving a first radiation beam at a Bragg angle and diffracting the first radiation beam, and for receiving a second radiation beam at a non-Bragg angle and transmitting the second radiation beam undiffracted, the first and second radiation beams having an angle of deviation of less than 2° before entering the hologram assembly.

Claim 10

A hologram system comprising: a first substrate; a first volume hologram overlying the first substrate, the first volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 1 relative to an exterior planar surface of the first volume hologram, and each Bragg plane spaced a distance L 1 apart; a second substrate; a second volume hologram overlying the second substrate, the second volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 2 relative to an exterior planar surface of the second volume hologram, and each Bragg plane spaced a distance L 2 apart, Φ 2 being equal to Φ 1 and L 2 being equal to L 1 , the second volume hologram being oriented with its Bragg planes parallel with the Bragg planes of the first volume hologram; and an optical cement connecting the first volume hologram to the second volume hologram.

Claim 11

A hologram system comprising: a first substrate; a first volume hologram overlying the first substrate, the first volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 1 relative to an exterior planar surface of the first volume hologram, and each Bragg plane spaced a distance L 1 apart; a second substrate; a second volume hologram overlying the second substrate, the second volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 2 relative to an exterior planar surface of the second volume hologram, and each Bragg plane spaced a distance L 2 apart, Φ 2 being equal to Φ 1 and L 2 being equal to L 1 , the second volume hologram being oriented with its Bragg planes parallel with the Bragg planes of the first volume hologram; and an optical cement connecting the first volume hologram to the second volume hologram.

Claim 12

The system of claim 9, wherein the first and second volume holograms have the same thickness.

Claim 13

The system of claim 9, wherein the combined thickness of the first and second volume holograms is T, where T≧25 microns.

Claim 14

The system of claim 9, wherein the first and second substrates are located on opposite sides of the first and second volume holograms.

Claim 15

The system of claim 9, wherein the optical cement is a radiation cured cement.

Claim 16

The system of claim 9, wherein the first and second volume holograms are made from separate pieces of a single volume hologram.

Claim 17

The system of claim 9, wherein the first and second volume holograms are made of dichromated gelatin.

Claim 18

The system of claim 9, wherein the first and second volume holograms comprise a hologram assembly, the hologram assembly for receiving a first radiation beam at a Bragg angle and diffracting the first radiation beam, and for receiving a second radiation beam at a non-Bragg angle and transmitting the second radiation beam undiffracted, the first and second radiation beams having an angle of deviation of less than 2° before entering the hologram assembly.

Claim 21

The method of claim 17, further comprising the step of securing the relative positions of the first and second volume holograms.

Claim 22

The method of claim 17, further comprising the step of placing a cement between the first volume hologram and the second volume hologram and curing the cement to bond the first and second volume holograms together.

Claim 23

The method of claim 19, wherein the cement is a radiation cured cement and the curing is achieved by directing radiation at the cement.

Claim 24

The method of claim 17, further including the step of passing a laser beam through the first and second volume holograms and measuring the diffraction of the laser beam in order to determine the alignment between the first and second volume holograms.

Claim 25

The method of claim 17, wherein the first and second volume holograms have the same thickness.

Claim 26

The method of claim 17, wherein the combined thickness of the first and second volume holograms is T, where T≧ to 25 microns.

Claim 27

The method of claim 17, wherein the first and second volume holograms have a first and a second substrate in supporting relationship, respectively, the first and second substrates located on opposite sides of the first and second volume holograms.

Claim 28

The method of claim 17, wherein the first and second volume holograms are made from separate pieces of a single volume hologram.

Claim 29

The method of claim 17, wherein the first and second volume holograms are made of dichromated gelatin.

Claim 30

The method of claim 17, wherein the steps of rotationally and translationally moving the first and second volume holograms is done with the first and second volume holograms located in an optical stage.

Claim 31

A hologram system made using the process of claim 17.

Claim 32

A hologram system comprising: an optical data storage medium; a radiation source for generating two radiation beams having an angle of divergence; a transmission means for transmitting the two radiation beams to the medium; a reception means for receiving two reflected radiation beams from the medium; and a hologram assembly for receiving and separating the two reflected radiation beams comprising a first volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 1 relative to an exterior planar surface of the first volume hologram, and each Bragg plane spaced a distance L 1 apart, and a second volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 2 relative to an exterior planar surface of the second volume hologram, and each Bragg plane spaced a distance L 2 apart, Φ 2 being equal to Φ 1 and L 2 being equal to L 1 , the second volume hologram oriented with its Bragg planes parallel with the Bragg planes of the first volume hologram, and means for optically coupling the first and second volume holograms.

Claim 33

A hologram system comprising: an optical data storage medium; a radiation source for generating two radiation beams having an angle of divergence; a transmission means for transmitting the two radiation beams to the medium; a reception means for receiving two reflected radiation beams from the medium; and a hologram assembly for receiving and separating the two reflected radiation beams comprising a first volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 1 relative to an exterior planar surface of the first volume hologram, and each Bragg plane spaced a distance L 1 apart, and a second volume hologram having a plurality of Bragg planes, each Bragg plane set at an angle Φ 2 relative to an exterior planar surface of the second volume hologram, and each Bragg plane spaced a distance L 2 apart, Φ 2 being equal to Φ 1 and L 2 being equal to L 1 , the second volume hologram oriented with its Bragg planes parallel with the Bragg planes of the first volume hologram, and means for optically coupling the first and second volume holograms.

Claim 34

The system of claim 29, wherein the first and second volume holograms have the same thickness.

Claim 35

The system of claim 29, wherein the combined thickness of the first and second volume holograms is T, where T≧25 microns.

Claim 36

The system of claim 29, further including a first and a second substrate in supporting relationship to the first and second holograms, respectively, the first and second substrates located on opposite sides of the first and second holograms.

Claim 37

The system of claim 29, wherein the optical coupling means is a radiation cured cement.

Claim 38

The system of claim 29, wherein the first and second volume holograms are made from separate pieces of a single volume hologram.

Claim 39

The system of claim 29, wherein the first and second volume holograms are made of dichromated gelatin.

Claim 40

The system of claim 29, wherein the hologram assembly for receiving a first radiation beam at a Bragg angle and diffracting the first radiation beam, and for receiving a second radiation beam at a non-Bragg angle and transmitting the second radiation beam undiffracted, the first and second radiation beams having an angle of deviation of less than 2° before entering the hologram assembly.