Reply #3: Not likely to be an efficient path...

[skids]

...but there are a couple things that are close.

One is this here, that captures light in a mirror box full of fluorescent material, transforming it to a single frequency band which hits tuned solar cell strips mounted on the edges:

http://www.solgel.com/articles/Sept01/ren_solar.htm

A second one is pushing the carnot limit with a system that emits tuned light from a heated element to be harnessed by tuned solar cells:

http://en.wikipedia.org/wiki/Thermophotovoltaic

Finally if you just have a soundwave fetish there's thermoacoustic heat engines:

http://www.acs.psu.edu/users/sinclair/thermal/sundrive.html