We report a beam shaping system for generating high intensity programmable optical
spots using mGPC: matched filtering combined with Generalized Phase Contrast
applying two consumer handheld pico-projectors. Such a system presents a low cost
alternative for optical trapping and manipulation, optical lattices and other beam
shaping applications usually implemented with high-end spatial light modulators.
Portable pico-projectors based on liquid crystal on silicon (LCoS) devices were used
as binary phase-only spatial light modulators by setting the appropriate polarization of
the illumination. They were subsequently placed into the object and Fourier plane of a
4f-setup based on the mGPC configuration. Having a dynamic spatial phase filter,
instead of a fabricated one, allows the beam shaper to adapt to different input phase
patterns suited for different requirements. Despite imperfections in these consumer
pico-projector LCoS-devices, the mGPC approach tolerates phase aberrations that
would have otherwise been contrasted by a standard phase imaging technique.