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Chromatic Correction for a Laser Diode/Holographic Deflector

IP.com Disclosure Number: IPCOM000043926D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Sincerbox, GT: AUTHOR

Abstract

A holographic deflector for a laser imaging system is described in which an additional holographic element is provided to correct for aberrations caused by a wavelength shift in the laser source compared to the original design wavelength. A laser imaging system is shown in Fig. 1 which comprises a disk 10 having n identical holographic facets brought successively to be illuminated with laser illuminating beam 12. If the optical/holographic system is designed to operate at wavelength g1, then a scan line 14 is produced as each facet of the hologram passes laser beam 12 when the laser output is at wavelength g1 . However, some laser source outputs (GaAs laser diodes, for example) vary with production, aging, temperature, and drive current so that, should the laser output wavelength be g2, then the scan line 16 would be produced.

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Chromatic Correction for a Laser Diode/Holographic Deflector

A holographic deflector for a laser imaging system is described in which an additional holographic element is provided to correct for aberrations caused by a wavelength shift in the laser source compared to the original design wavelength. A laser imaging system is shown in Fig. 1 which comprises a disk 10 having n identical holographic facets brought successively to be illuminated with laser illuminating beam 12. If the optical/holographic system is designed to operate at wavelength g1, then a scan line 14 is produced as each facet of the hologram passes laser beam 12 when the laser output is at wavelength g1 . However, some laser source outputs (GaAs laser diodes, for example) vary with production, aging, temperature, and drive current so that, should the laser output wavelength be g2, then the scan line 16 would be produced. To compensate for this difference in laser output compared to the design wavelength, an additional holographic element 18 (Fig. 2) is fixed in position near disk 10. Holographic element 18 is recorded identically to one facet of the disk 10. By illuminating this hologram 18 with a beam conjugate to the original object beam 20, it reconstructs a wave conjugate to the original reference beam 22. This beam now illuminates the facets just as in Fig. 1 when there is no wavelength change. Since we are using collimated beams, the slight lateral shift caused by the finite separation of th...