Chemically responsive switching elements

Reports the development of a gas sensitive device based on integrated optics technology, in which the sensing medium is a cladding upon an optical waveguide. In these devices, the change in optical properties of organic molecules when affected by the gas causes a change in the propagation characteristics of the guided light in the waveguide. The evanescent field of the guided light is perturbed by enhanced absorption and modified refractive index in the organic film after gas exposure. The device described uses waveguide claddings of organic molecules deposited by means of the Langmuir-Blodgett (LB) technique, in which compressed organic monolayers are repeatedly deposited from an aqueous subphase onto a solid substrate to form multilayer films. This technique has the advantage that chemically active molecules, such as organic dyes, can be incorporated into the films