Holographic techniques significantly extend the capabilities of laser
tweezing, making possible extended trapping patterns for manipulating large
numbers of particles and volumes of soft matter. We describe practical methods
for creating arbitrary configurations of optical tweezers using
computer-generated diffractive optical elements. While the discussion focuses
on ways to create planar arrays of identical tweezers, the approach can be
generalized to three-dimensional arrangements of heterogeneous tweezers and
extended trapping patterns.Comment: 8 pages, 9 Postscript figures, REVTeX source. For related materials,
see http://griergroup.uchicago.edu/~grier