Our ability to efficiently shape light has paved the way for a
host of important progress in photonics and biological research.
Starting from the pioneering work of Ashkin on radiation forces
[1], we have seen improvements on dynamic multiparticle optical
trapping primarily using diffractive beam shaping techniques such
as computer generated holography. Holography allows efficient
control of light by controlling the amplitude, phase or both, giving
rise to holographic optical tweezers (HOT) [2,3] which has become
an important tool in biology. An extension of the HOT is the
creation of optical landscapes for more complex optical traps [4]
and induced effects such as orbital angular momentum [5]. Recently, the use of simultaneous multi-site two-photon photolysis
to uncage neurotransmitters using holographic projection of
multiple focal spots has been reported [6]. The use of multiple
intense focal spots using diffractive optical elements [7] and microlens arrays [8] has unique applications in two-photon polymerization of multiple structures in parallel.
In all these applications, the need for high light throughput is
desirable. Moreover, it is also desirable to illuminate beam shaping
devices, such as spatial light modulators (SLMs), with a uniform
beam that matches the profile of the modulation element. Uniform
illumination is crucial when directly imaging the SLM pattern, e.g.
patterned light projections using digital micromirror devices