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

Bowman, R., D’Ambrosio, V., Rubino, E., Jedrkiewicz, O., Trapani, P. and Padgett, M. (2011) Optimisation of a low cost SLM for diffraction efficiency and ghost order suppression. European Physical Journal: Special Topics, 199(1), pp. 149-158. (doi:10.1140/epjst/e2011-01510-4)

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Publisher's URL: http://dx.doi.org/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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Padgett, Professor Miles and Bowman, Mr Richard
Authors: Bowman, R., D’Ambrosio, V., Rubino, E., Jedrkiewicz, O., Trapani, P., and Padgett, M.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:European Physical Journal: Special Topics
Publisher:Springer
ISSN:1951-6355
ISSN (Online):1951-6401
Published Online:07 December 2011

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
566181Optical Tweezers at Long Range and High Pressure (Creativity @ Home)Miles PadgettEngineering & Physical Sciences Research Council (EPSRC)EP/I034726/1Physics and Astronomy