SUBSTRATE COATED WITH NANOPARTICLES, AND USE THEREOF FOR THE DETECTION OF ISOLATED MOLECULES

摘要

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.