  Adaptive optics in combination with multi-photon techniques is a powerful
approach to image deep into a specimen. Remarkably, virtually all adaptive
optics schemes today rely on wavefront modulators which are reflective,
diffractive, or both. This, however, can pose a severe limitation for
applications. Here, we present a fast and robust sensorless adaptive optics
scheme adapted for transmissive wavefront modulators. We study our scheme in
numerical simulations and in experiments with a novel, optofluidic wavefront
shaping device which is transmissive, refractive, polarisation-independent and
broadband. We demonstrate scatter correction of two-photon-excited fluorescence
images of microbeads as well as brain cells and benchmark our device against a
liquid-crystal spatial light modulator. Our method and technology could open
new routes for adaptive optics in scenarios where previously the restriction to
reflective and diffractive devices may have staggered innovation and progress.
