A fiber-optic device for sensing the presence of a gas in an environment is provided. The device comprises a light source for directing a light beam to a layer system having a first surface and a second surface opposite the first surface. The first surface is exposable to the light beam and the ...http://www.google.com.au/patents/US5708735?utm_source=gb-gplus-sharePatent US5708735 - Fiber optic device for sensing the presence of a gas
