Abstract: The present disclosure relates to a substrate having a surface comprising nanoparticles or groups of nanoparticles which the linear optical response does not depend on the polarisation of the incident field of a Gaussian beam having an axis of propagation that is directed perpendicularly to the surface of the substrate. The shape or arrangement of the groups of nanoparticles has a Cn-type axis of symmetry perpendicular to the surface, where n is a number equal to three or greater than four, and the shape of the nanoparticles has a Cn-type axis of symmetry perpendicular to the surface, where n is a number no less than three, to allow strong enhancement of the beam close to the surface. The disclosure relates to use of substrates for detection and/or measurement of chemical, biochemical or biological molecules, wherein the molecules can be present in trace amounts in a liquid or other medium.

Abstract: The invention provides a multilayer structure comprising a dielectric substrate; a sticking layer that extends over a first face of the dielectric substrate; at least one layer of precious metal placed on the sticking layer, said sticking layer comprising a derivative of an alkylsilane, the layer of precious metal being applied by evaporation or by sputtering said precious metal. The invention also provides a method of fabricating said device based either on electron beam lithography, optical lithography or nanoimprint lithography.

Abstract: The invention relates to a device useful for non-invasive detection of the properties of a medium by means of interferometry. The device comprises an optical source which is used for illuminating a zone of the medium that is to be probed with a light beam, and an interferometer for splitting the light beam into a reference beam and a probe beam. The interferometer has a cutoff frequency for the automatic control of respective path lengths of the reference beam and of the probe beam. The device also comprises scanning means which, together with the probe beam, are used to scan the zone to be probed at an image acquisition frequency greater than the cutoff frequency.