US Patent 7674628 - Photoacoustic chemical sensor using nanoparticles

http://www.freepatentsonline.com/7674628.html

Photoacoustic sensing uses an effect in which an infrared laser emitted on a particular material produces sound. This patent from Applied Nanotech teaches using nanoparticles to enhance this effect. Claim 1 reads:

1. A process comprising the steps of:

a) exposing a deleterious chemical species to nanoparticles such that said chemical species adsorbs onto a surface of the nanoparticles as a chemical adsorbate;

b) irradiating the nanoparticles comprising the adsorbed deleterious chemical species;

c) locally detecting the adsorbed chemical species with a photoacoustic means and producing a signal comprising information regarding the presence of such chemical species; and

d) transmitting the signal to a remote location.