  We experimentally and numerically study the potential of
photoacoustic-guiding for light focusing through scattering samples via
wavefront-shaping and iterative optimization. We experimentally demonstrate
that the focusing efficiency on an extended absorber can be improved by
iterative optimization of the high frequency components of the broadband
photoacoustic signal detected with a spherically focused transducer. We
demonstrate more than 8-fold increase in the photoacoustic signal generated by
a 30 microns wire using a narrow frequency band around 60MHz. We numerically
confirm that such optimization leads to a smaller optical focus than using the
low frequency content of the photoacoustic feedback.
