US Patent 8030623 - CNT photoacoustic EM sensor

http://www.freepatentsonline.com/8030623.html

This patent from Hon Hai Precision (Foxconn) is based on the finding that carbon nanotubes act to convert electromagnetic waves (such as from a laser) into sound waves. Claim 1 reads: 

1. A method for measuring properties of an electromagnetic signal comprising steps of:

providing an electromagnetic signal measuring device comprising a carbon nanotube structure, the carbon nanotube structure comprising a plurality of carbon nanotubes;

receiving an electromagnetic signal by the carbon nanotube structure in the electromagnetic signal measuring device; and

measuring an intensity of the electromagnetic signal by sound waves produced by the carbon nanotube structure.