photoexcitation in neurophotonics research. Hence, we first tested
the GPC light shaper in a dynamic spot-projecting holographic
configuration. We performed a modified Gerchberg–Saxton algorithm [17,18] to compute the phase pattern necessary for generating a random arrangement of light spots. We have, however,
not optimized the phase to produce patterns with a reduced zeroorder and/or higher-order spurious diffraction. Holographic projections were demonstrated for both GPC-shaped and for hardtruncated input beams. The images captured by the beam profiler
are shown in Fig. 4 where we used the built-in despeckle filter of
the included software. The GPC-enhanced spots are more intense
than their hard-truncated counterparts and do not exhibit any
gross distortions, consistent with expectations from having a flat
illumination phase determined earlier. The intensity gain is
quantified using the ratio of the average light spot intensity in the
GPC-enhanced pattern to the corresponding average light spot
intensity in hard-truncated case (the zero order diffraction is not
included in the calculation).
Both the GPC-enhanced and hard-truncated readout beams
have flat phase making them suitable for phase modulation