Having a laser cutter these days isn’t a big deal. But [Chunlei Guo], a professor at the University of Rochester, has a powerful femto-second pulse laser and used it to create what might be the perfect solar absorber. You can see a video about the work, below.
It stands to reason that white materials reflect most light and therefore absorb less energy than black materials — this is part of what makes a radiometer work. Tungsten, in particular, is a good metal for absorbing solar power, but this new laser treatment — which builds nanostructures on the surface of the metal — increases efficiency by 130% compared to untreated tungsten.
The team has previously used a similar technology to make metals either hydrophilic or hydrophobic. The process gives the metal a black color which is where much of the efficiency comes from. According to reports, there’s still a 15% increase using the laser-treated surface over a piece of plain black tungsten.
We’d like some of this for our solar pool heater. We doubt that is using tungsten to start with, so maybe that’s the first retrofit. There are plenty of non-tungsten designs. We are more likely to find tungsten in our light bulbs or our metal-shaping tools.