The European Physical Journal Special Topics

, Volume 199, Issue 1, pp 149–158

Optimisation of a low cost SLM for diffraction efficiency and ghost order suppression

Authors

    • School of Physics and Astronomy, SUPAUniversity of Glasgow
  • V. D’Ambrosio
    • Università degli Studi di Roma “La Sapienza”
  • E. Rubino
    • CNISM and Università degli Studi dell’Insubria
  • O. Jedrkiewicz
    • CNISM and Università degli Studi dell’Insubria
  • P. Di Trapani
    • CNISM and Università degli Studi dell’Insubria
  • M. J. Padgett
    • School of Physics and Astronomy, SUPAUniversity of Glasgow
Regular Article

DOI: 10.1140/epjst/e2011-01510-4

Cite this article as:
Bowman, R., D’Ambrosio, V., Rubino, E. et al. Eur. Phys. J. Spec. Top. (2011) 199: 149. doi:10.1140/epjst/e2011-01510-4

Abstract

Spatial Light Modulators (SLMs) are a powerful tool in many optics laboratories, but due to the technology required for their fabrication, they are usually very expensive. Recently some inexpensive devices have been produced, however their phase shift range is less than 2π, leading to a loss of diffraction efficiency for the SLM. We show how to improve the first order diffraction efficiency of such an SLM by adjusting the blazing function, and obtain a 1.5 times increase in first order diffracted power. Even a perfect SLM with 2π phase throw can produce undesired effects in some situations; for example in holographic optical tweezers it is common to find unwanted “ghost spots” near to the array of first-order spots. Modulating the amplitude, by spatially modulating the blazing function, allows us to suppress the ghost spots. This increases the contrast between desired and unwanted spots by more than an order of magnitude.

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Copyright information

© EDP Sciences and Springer 2011