As outlined in the AIP’s Journal of Renewable and Sustainable Energy, the new solar lasers would concentrate light with a small parabolic mirror 1 meter in diameter that has a focal spot approximately 2-3 centimeters in diameter. The concentrated light would then strike a two-layer ceramic disk known as a Neodymium and Chromium co-doped YAG (yttrium aluminum garnet) laser material.
One side of the disk would have a highly reflective coating; the other side would be anti-reflecting. When sunlight penetrates through the ceramic material, it excites the electrons in the material, causing them to emit laser light of a specific wavelength (1.06 micrometers). To control the searing heat produced by the concentrated sunlight, the ceramic disk would be mounted atop a heat sink through which water would be pumped.
The laser light would then travel to a prime focus and be reflected back to the ceramic surface before exiting the solar collector at an oblique angle. It’s this "double pass" path that produces the gain in efficiency, enabling a greater fraction of sunlight to be converted into laser light. Potentially, parabolic reflector lasers could be harnessed for the large-scale synthesis of nanoparticles and nanostructures.