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  • Research Article
  • Open Access

Design of Extended Depth-of-Focus Laser Beams Using Orthogonal Beam Expansions

EURASIP Journal on Advances in Signal Processing20052005:618172

  • Received: 16 April 2004
  • Published:


Laser beams with extended depth of focus have many practical applications, such as scanning printed bar codes. Previous work has concentrated on synthesizing such beams by approximating the nondiffracting Bessel beam solution to the wave equation. In this paper, we introduce an alternate novel synthesis method that is based on maintaining a minimum MTF value (contrast) over the largest possible distance. To achieve this, the coefficients of an orthogonal beam expansion are sequentially optimized to this criterion. One of the main advantages of this method is that it can be easily generalized to noncircularly symmetrical beams by the appropriate choice of the beam expansion basis functions. This approach is found to be very useful for applications that involve scanning of the laser beam.

Keywords and phrases

  • lasers
  • beam shaping
  • optical transfer functions
  • propagation
  • extended depth of focus
  • orthogonal beam expansion

Authors’ Affiliations

Symbol Technologies Inc., One Symbol Plaza, Holtsville, NY 11742-1300, USA
Mitsubishi Electric Research Laboratories, 201 Broadway, Cambridge, MA 02139, USA


© Goren et al. 2005