Abstract: A spaser device comprises a graphene resonator and a carbon nanotube (CNT) gain element coupled via exciton-plasmon interaction. The graphene resonator may be a rectangular or square graphene nanoflake (GNF), and the CNT gain element may be characterized by chirality vector (n,m) selected such that the CNT has semiconducting properties. The CNT gain element may be illuminated using a light source having a photon energy corresponding with a first exciton energy (E22) of the CNT, whereby excitons having a second exciton energy (E11) less than the first exciton energy are generated in the CNT, and coupled to a surface plasmon (SP) mode of the graphene resonator. When the rate of generation of excitons having the second exciton energy exceeds a gain threshold, continuous spasing is established within the spaser device.

Abstract: A spaser device comprises a graphene resonator and a carbon nanotube (CNT) gain element coupled via exciton-plasmon interaction. The graphene resonator may be a rectangular or square graphene nanoflake (GNF), and the CNT gain element may be characterised by chirality vector (n,m) selected such that the CNT has semiconducting properties. The CNT gain element may be illuminated using a light source having a photon energy corresponding with a first exciton energy (E22) of the CNT, whereby excitons having a second exciton energy (E11) less than the first exciton energy are generated in the CNT, and coupled to a surface plasmon (SP) mode of the graphene resonator. When the rate of generation of excitons having the second exciton energy exceeds a gain threshold, continuous spasing is established within the spaser device.

Abstract: A magnetic circuit (400) comprises a magnetic path which includes at least one magnetic source (102) arranged to generate magnetic flux within the magnetic path. A magnetic flux-concentrating element 402 is magnetically coupled to the magnetic source, and arranged to concentrate magnetic-flux generated by the magnetic source within a volume adjacent to the magnetic flux-concentrating element (402). Some embodiments of the magnetic circuit (400) comprise at least first (102) and second (104) magnetic sources, which may advantageously be arranged to generate magnetic flux in a common direction within the magnetic path.

Abstract: The present invention relates to the field of phase measurement, particularly optical phase measurement. In one form, the invention relates to a method and device for measuring the phase between distinct signals by converting phase variations between the signals into amplitude variations. In one embodiment the invention provides a method of arranging the structure of a two-dimensional or three-dimensional crystal to measure the phase between signals, comprising the steps of (i) providing a respective waveguide for each signal and (ii) providing a micro-cavity array arranged to provide a resonance output in response to the phase of the signals. The invention has application to a wide range of apparatus and devices across many industries including communications, food technology, pharmacology, medicine and biology.