  Light propagation in materials with microscopic inhomogeneities is affected
by scattering. In scattering materials, such as powders, disordered
metamaterials or biological tissue, multiple scattering on sub-wavelength
particles makes light diffuse. Recently, we showed that it is possible to
construct a wavefront that focuses through a solid, strongly scattering object.
The focusing wavefront uniquely matches a certain configuration of the
particles in the medium. To focus light through a turbid liquid or living
tissue, it is necessary to dynamically adjust the wavefront as the particles in
the medium move. Here we present three algorithms for constructing a wavefront
that focuses through a scattering medium. We analyze the dynamic behavior of
these algorithms and compare their sensitivity to measurement noise. The
algorithms are compared both experimentally and using numerical simulations.
The results are in good agreement with an intuitive model, which may be used to
develop dynamic diffusion compensators with applications in, for example, light
delivery in human tissue.
