Abstract

Using a phase-only spatial light modulator (SLM) in a Fourier transform setup together with fast diffractive optics design algorithms provides a way to automatically generate complex and rapidly changing laser illumination patterns in the far-field. We propose a hierarchical software structure for the adaptive, on-line design of far-field illumination patterns. Using the on-line design system together with camera feedback of the illuminated scene would make it possible to detect and actively laser designate multiple objects in parallel. Possibilities for multispot, arbitrary trajectory scanning and also broad-area speckle-reduced illumination are demonstrated with experimentally measured diffraction pattern sequences from a 120×128 pixel phase-only SLM.

© Optical Society of America

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References

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  1. U. Krackhardt, J.N. Mait, and N. Streibl, "Upper bound on the diffraction efficiency of phase-only fanout elements," Appl. Opt. 31, 27-37 (1992).
    [CrossRef] [PubMed]
  2. R. W. Cohn and L. G. Hassebrook, "Representations of fully complex functions on real-time spatial light modulators," Ch. 15, pp. 396-432 in Optical information processing, F. T. S. Yu and S. Jutamulia, eds. (Cambridge U. Press., Cambridge, UK, 1998).
  3. Galvanometer scanners and accessories, http://www.gsilumonics.com/c03oem_gal_frame/galvoframe.html
  4. Cambridge Technology Products, http://www.camtech.com/prods4a.htm
  5. NEOS online catalog, http://www.neostech.com/neos/catalog
  6. Isomet Corporation deflectors, http://www.isomet.com/deflectors.html
  7. Boulder Nonlinear Systems, Inc., http://www.bnonlinear.com
  8. T. H. Lin, "Implementation and characterization of a flexure-beam micromechanical spatial light modulator," Opt. Eng. 33, 3643-3648 (1994).
    [CrossRef]
  9. M. Duelli, M. Reece, and R. W. Cohn, "Modified minimum distance criterion for blended random and nonrandom encoding," J. Opt. Soc. Am. A 16, 2425-2438 (1999).
    [CrossRef]
  10. M. Duelli, R. W. Cohn, "Pseudorandom encoding for real-valued ternary spatial light modulators," Appl. Opt. 38, 3804-3809 (1999).
    [CrossRef]
  11. L. Ge, M. Duelli, and R. W. Cohn, "Improved-fidelity error diffusion through blending with pseudorandom encoding," J. Opt. Soc. Am. A 17, 1606-1616 (2000).
    [CrossRef]
  12. R. W. Cohn and M. Liang, "Approximating fully complex spatial modulation with pseudo-random phase-only modulation," Appl. Opt. 33, 4406-4415 (1994).
    [CrossRef] [PubMed]
  13. R. W. Cohn and M. Duelli, "Ternary pseudorandom encoding of Fourier transform holograms," J. Opt. Soc. Am. A 16, 71-84 and "errata," 1089-1090 (1999).
    [CrossRef]
  14. R. D. Juday, "Optimal realizable filters and the minimum Euclidean distance principle," Appl. Opt. 32, 5100-5111 (1993).
    [CrossRef] [PubMed]
  15. Y. Yang, H. Stark, D. Gurken, C. L. Lawson, and R. W. Cohn, "High-diffraction-efficiency pseudorandom encoding," J. Opt. Soc. Am. A 17, 285-293 (2000).
    [CrossRef]
  16. J. N. Mait, "Understanding diffractive optic design in the scalar domain," J. Opt. Soc. Am. A 12, 2145-2158 (1995).
    [CrossRef]
  17. D. Jared and D. Ennis, "Inclusion of filter modulation in synthetic discriminant function construction," Appl. Opt. 28, 232-239 (1989).
    [CrossRef] [PubMed]
  18. N.C. Gallagher and B. Liu, "Method for computing kinoforms that reduces image reconstruction error," Appl. Opt. 12, 2328-2335 (1973).
    [CrossRef] [PubMed]
  19. R. W. Cohn, "Adaptive real-time architectures for phase-only correlation," Appl. Opt. 32, 718-725 (1993).
    [CrossRef] [PubMed]
  20. M. S. Vangular, Optimization methods for diffraction gratings and composite matched filters, M.S. Thesis, University of Louisville (1998).
  21. J. A. Davis and D. M. Cottrell, "Random mask encoding of multiplexed phase-only and binary phase-only filters," Opt. Lett. 19, 496-498 (1994).
    [CrossRef] [PubMed]

Other (21)

U. Krackhardt, J.N. Mait, and N. Streibl, "Upper bound on the diffraction efficiency of phase-only fanout elements," Appl. Opt. 31, 27-37 (1992).
[CrossRef] [PubMed]

R. W. Cohn and L. G. Hassebrook, "Representations of fully complex functions on real-time spatial light modulators," Ch. 15, pp. 396-432 in Optical information processing, F. T. S. Yu and S. Jutamulia, eds. (Cambridge U. Press., Cambridge, UK, 1998).

Galvanometer scanners and accessories, http://www.gsilumonics.com/c03oem_gal_frame/galvoframe.html

Cambridge Technology Products, http://www.camtech.com/prods4a.htm

NEOS online catalog, http://www.neostech.com/neos/catalog

Isomet Corporation deflectors, http://www.isomet.com/deflectors.html

Boulder Nonlinear Systems, Inc., http://www.bnonlinear.com

T. H. Lin, "Implementation and characterization of a flexure-beam micromechanical spatial light modulator," Opt. Eng. 33, 3643-3648 (1994).
[CrossRef]

M. Duelli, M. Reece, and R. W. Cohn, "Modified minimum distance criterion for blended random and nonrandom encoding," J. Opt. Soc. Am. A 16, 2425-2438 (1999).
[CrossRef]

M. Duelli, R. W. Cohn, "Pseudorandom encoding for real-valued ternary spatial light modulators," Appl. Opt. 38, 3804-3809 (1999).
[CrossRef]

L. Ge, M. Duelli, and R. W. Cohn, "Improved-fidelity error diffusion through blending with pseudorandom encoding," J. Opt. Soc. Am. A 17, 1606-1616 (2000).
[CrossRef]

R. W. Cohn and M. Liang, "Approximating fully complex spatial modulation with pseudo-random phase-only modulation," Appl. Opt. 33, 4406-4415 (1994).
[CrossRef] [PubMed]

R. W. Cohn and M. Duelli, "Ternary pseudorandom encoding of Fourier transform holograms," J. Opt. Soc. Am. A 16, 71-84 and "errata," 1089-1090 (1999).
[CrossRef]

R. D. Juday, "Optimal realizable filters and the minimum Euclidean distance principle," Appl. Opt. 32, 5100-5111 (1993).
[CrossRef] [PubMed]

Y. Yang, H. Stark, D. Gurken, C. L. Lawson, and R. W. Cohn, "High-diffraction-efficiency pseudorandom encoding," J. Opt. Soc. Am. A 17, 285-293 (2000).
[CrossRef]

J. N. Mait, "Understanding diffractive optic design in the scalar domain," J. Opt. Soc. Am. A 12, 2145-2158 (1995).
[CrossRef]

D. Jared and D. Ennis, "Inclusion of filter modulation in synthetic discriminant function construction," Appl. Opt. 28, 232-239 (1989).
[CrossRef] [PubMed]

N.C. Gallagher and B. Liu, "Method for computing kinoforms that reduces image reconstruction error," Appl. Opt. 12, 2328-2335 (1973).
[CrossRef] [PubMed]

R. W. Cohn, "Adaptive real-time architectures for phase-only correlation," Appl. Opt. 32, 718-725 (1993).
[CrossRef] [PubMed]

M. S. Vangular, Optimization methods for diffraction gratings and composite matched filters, M.S. Thesis, University of Louisville (1998).

J. A. Davis and D. M. Cottrell, "Random mask encoding of multiplexed phase-only and binary phase-only filters," Opt. Lett. 19, 496-498 (1994).
[CrossRef] [PubMed]

Supplementary Material (11)

» Media 1: MOV (1664 KB)     
» Media 2: MOV (2477 KB)     
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» Media 10: MOV (1155 KB)     
» Media 11: MOV (338 KB)     

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Figures (9)

Fig. 1.
Fig. 1.

(a) The proposed hierarchical design system, (b) the iterative Fourier transform algorithm. In (a) Level 1 design is indicated by black lines and boxes. With the addition of the algorithmic portions indicated by red and blue lines, the algorithm becomes a Level 2 or Level 3 design respectively. The errors between the target and resulting intensities (dashed blue line) can be used to compensate the desired function, and this procedure, which is similar to adjustment of the free phases, also is classified as Level 3 design.

Fig. 2.
Fig. 2.

(a) (1.62 MB) Movie of arbitrary scanning by SLM, (b) image with (0,0) to (1,1) orders indicated

Fig. 3.
Fig. 3.

. Movies of sidelobe generation by (a) MD-PRE (2.41 MB) and by (b) MDE (2.41 MB)

Fig. 4.
Fig. 4.

(1.91 MB) Movie of translation of a fixed pattern.

Fig. 5.
Fig. 5.

Movies of continuous scanning (a) by composition (579 KB) and (b) by 128×128 IFFT (611 KB). The fixed images in this figure are the summations of the images from the entire sequence.

Fig. 6.
Fig. 6.

Movie of (a) parallel replicated scanning by periodic sampling (2.13 MB) and (b) by non-replicated scanning by random sampling (2.23 MB) of the elementary functions.

Fig. 7.
Fig. 7.

Movie of multiple widened spots (a) by parallel division of the SLM into multiple SLM’s (578 KB) and (b) by adding two sets or layers of spatially multiplexed functions together (1.12 MB.)

Fig. 8.
Fig. 8.

Image of (a) individual realizations of the spot array (337 KB) and (b) average result of 50 individual realizations of the spot array.

Fig. 9.
Fig. 9.

Image of (a) individual realization of a speckle-illuminated coin and (b) average result of 50 individual realizations of the speckle-illuminated coin.

Tables (1)

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Table 1. Information on diffraction pattern images, design method and theoretical performance

Equations (1)

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a ' c ( x ) = i = 1 M g i ( x ) exp [ j ( 2 π f i x + ϕ i ) ] .

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