Patent ID: 8649014

Claim:
An optical device, comprising; a first optical branch formed at an interface between a first substrate and a second substrate; and a second optical branch formed at an interface between the second substrate and an ambient medium, wherein the second substrate defines first and second spaced apart slits that are each coupled to the first and second optical branches, the first slit configured to receive at least partially coherent light from a broad bandwidth white light source and in response excite at least one surface plasmon polariton mode in each of the first and second optical branches, and the second slit configured to combine the surface plasmon polariton modes received from the first and second optical branches and emit scattered light into at least one of the first substrate and the ambient medium; wherein the surface plasmon polariton modes received from the first and second optical branches constructively and destructively interfere with each other at the second slit; wherein the slit separation is at a distance for white light to maintain coherence before detection by a detector.