  We present a minimally-invasive endoscope based on a multimode fiber that
combines photoacoustic and fluorescence sensing. From the measurement of a
transmission matrix during a prior calibration step, a focused spot is produced
and raster-scanned over a sample at the distal tip of the fiber by use of a
fast spatial light modulator. An ultra-sensitive fiber-optic ultrasound sensor
for photoacoustic detection placed next to the fiber is combined with a
photodetector to obtain both fluorescence and photoacoustic images with a
distal imaging tip no larger than 250um. The high signal-to-noise ratio
provided by wavefront shaping based focusing and the ultra-sensitive ultrasound
sensor enables imaging with a single laser shot per pixel, demonstrating fast
two-dimensional hybrid imaging of red blood cells and fluorescent beads.
