Method and apparatus for recoding holographic diffraction gratings
A method and apparatus for scanning an input beam of light in a two dimensional pattern; splitting the scanned input beam of light into two output beams of light, each one of the two output beams of light passing along a different path to a common region in a recording medium, such region scanning the recording medium during the scanning of the input beam of light to produce a diffraction grating in the recording medium by interference between the two output beams of light.
1. A method, comprising:
continuously scanning an input beam of light in a two dimensional pattern;
splitting the scanned input beam of light into two output beams of light, each one of the two output beams of light passing along a different path to strike a recording medium, such recording medium having a front side and a back side, such two output beams being directed to strike a common region from the same one of either the front side or back side of the recording medium, such region scanning the recording medium and being concurrently recorded by the scanning medium continuously during the continuous scanning of the input beam of light to produce a diffraction grating in the recording medium by interference between the two output beams of light; such splitting comprising:
directing the scanned input beam to an optical system comprising a beam splitter mirror and three mirrors for directing each one of the two output beams of light along a corresponding one of the different paths to the common region on the recording medium, one of the two beams reflecting from a first one of the three of mirrors and the other one of the two beams reflecting from a second one and a third one of the three mirrors.
2. The method recited in claim 1 wherein the optical system between the beam splitter mirror and the recording medium is a totally reflective system.
3. A method, comprising:
scanning an input beam of light in a two dimensional pattern;
splitting the scanned input beam of light into two output beams of light, each one of the two output beams of light passing along a different path to strike a recording medium, such recording medium having a front side and a back side, such two output beams being directed to strike the common region from the same one of either the front side or back side of the recording medium, such region scanning the recording medium during the scanning of the input beam of light to produce a diffraction grating in the recording medium by interference between the two output beams of light; such splitting comprising:
directing the scanned input beam to an optical system comprising a beam splitter mirror and three mirrors for directing each one of the two output beams of light along a corresponding one of the different paths to the common region on the recording medium, one of the two beams reflecting from a first one of the three mirrors and the other one of the two beams reflecting from a second one and a third one of the three mirrors; and
wherein the two output beams of light maintain a substantially constant cross section as such beams pass from the beam splitter mirror to the common region in the recording medium.
4. The method recited in claim 3 wherein the cross section has a Gaussian amplitude distribution.
5. The method recited in claim 3 wherein the optical system between the beam splitter mirror and the recording medium is a totally reflective system.
6. Apparatus, comprising:
scanning apparatus for scanning an input beam of light in a two dimensional pattern;
a recording medium having a front side and a back side;
a beam splitter for splitting the scanned input beam of light into two output beams of light;
an optical system comprising a plurality of mirrors for directing each one of the two output beams of light passing along a different path to strike a common region on the same one of either the front side or the back side of the recording medium, such region scanning the recording medium continuously recorded by the recording medium during continuous scanning of the input beam of light to produce a diffraction grating in the recording medium by interference between the two output beams of light; such optical system comprising: a beam splitter mirror and a plurality of mirrors for directing each one of the two output beams of light along a corresponding one of the different paths to the common region on the recording medium, one of the two beams reflecting from a first one of the plurality of mirrors and the other one of the two beams reflecting from a second one and then a third one of the plurality of mirrors.
7. The apparatus recited in claim 6 wherein the two output beams of light maintain a substantially constant cross section between the beam splitter and the recording medium.
8. The apparatus recited in claim 7 wherein the cross section has a Gaussian amplitude distribution.
9. The apparatus recited in claim 7 wherein the optical system between the beam splitter and the recording medium is a totally reflective system.
10. The apparatus recited in claim 6 wherein the optical system between the beam splitter and the recording medium is a totally reflective system.
11. A method, comprising:
scanning an input beam of light in a two dimensional pattern during recording;
splitting the scanned input beam of light into two output beams of light, each one of the two output beams of light passing along a different path to strike a recording medium, such recording medium having a front side and a back side, such two output beams being directed to strike the common region from the same one of either the front side or back side of the recording medium, such region scanning the recording medium during the scanning of the input beam of light to produce a diffraction grating in the recording medium by interference between the two collimated output beams of light where a scanning pattern provides a homogeneous distribution of exposure dosage over the area of recording medium.
12. The method recited in claim 11 wherein the splitting comprises:
directing the scanned input beam to an optical system comprising a beam splitter mirror and a plurality of mirrors for directing each one of the two output beams of light along a corresponding one of the different paths to the common region on the recording medium, one of the two beams reflecting from a first one of the plurality mirrors and the other one of the two beams reflecting from a second and a third one of the plurality of mirrors.
13. The method recited in claim 12 wherein the two output beams of light maintain a substantially constant cross section as such beams pass between the beam splitter and the common region in the recording medium.
14. The method recited in claim 13 wherein the optical system between the beam splitting and the recording medium is a totally reflective system.
15. The method recited in claim 12 wherein the optical system between the beam splitting and the recording medium is a totally reflective system.
16. The method recited in claim 11 wherein the two output beams of light maintain a substantially constant cross section as such beams pass between the beam splitter and the common region in the recording medium.
17. The method recited in claim 16 wherein the optical system between the beam splitting and the recording medium is a totally reflective system.
18. The method recited in claim 11 wherein the optical system between the beam splitter and the recording medium is a totally reflective system.