  We present a simple and robust approach to reduce laser speckle, which has
limited the adoption of lasers in imaging and display applications. We use
colloidal solutions that can quickly reduce speckle contrast due to the
Brownian motion of the scattering particles. The high insertion loss associated
with propagation through a colloidal solution was overcome by using white paint
to cover the sides of the cuvette and an optical fiber to deliver the laser
light deep into the colloidal solution, enabling transmission greater than 90%.
The diffused laser output followed a Lambertian distribution and produced
speckle contrast below 4% at an integration time of 129 {\mu}s. The ability for
colloidal solutions to achieve fast speckle reduction without power consumption
while maintaining high transmission, low cost, a compact size, and a long
lifetime, makes our approach useful for a wide range of laser imaging and
projection applications.
