Abstract: A piezoelectric sensor for the detection and characterization of at least one biochemical element in a fluid, has a piezoelectric substrate exhibiting at each of its opposite faces at least one conducting surface forming electrodes, the electrodes being linked to an electrical generator, one at least of the surfaces being wrapped in a functionalized film, the electrodes form transmission lines exhibiting a zone constituting an induction loop for the excitation of the piezoelectric substrate, the link between the electrodes and the generator being ensured by inductive coupling. A system implementing such a sensor, as well as applications of such a sensor, are described.

Abstract: The invention relates to a transparent sol-gel material which has a susceptibility of the second order X.sub.2, consisting of an inorganic matrix containing organic molecules which have nonlinear optical properties (ONLAOM) oriented in a preferential direction. The materials according to the invention lend themselves to the production of components making use of their linear and nonlinear optical properties (optical telecommunications, processing of the optical signal in analog or digital form, and the like).