Abstract: A method for determining one or more properties of a molecular metal ligand in a sample comprises the steps of: providing a quantum sensor: exposing the quantum sensor to the sample: applying an illumination signal to the quantum sensor for a first predetermined duration: and detecting a photoluminescence intensity emitted from the quantum sensor. A characteristic of the detected photoluminescence intensity is indicative of one of the properties of the molecular metal ligand in the sample.

Abstract: This disclosure relates to an electrical field sensor. The sensor comprises a diamond substrate with a conducting surface providing positive charge carriers and multiple defects disposed in the diamond substrate. The sensor further comprises an optical apparatus to initialise and readout the multiple defect vacancies to determine the electrical field based on a detected fluorescence of the multiple defects. The multiple defects are located at a depth below the surface to enable the positive charge carriers to reach and positively charge the multiple defect vacancies under an influence of an external negative electric field to thereby alter the fluorescence of at least some of the multiple defects. Since the fluorescence can be measured optically, no electrical connections or amplifiers are required on the surface, which means significantly higher densities of sensors can be implemented.

Abstract: The present disclosure provides a method of fabricating a single photon source. The method comprises the steps of providing a substrate with a visual feature and providing a plurality of particles positioned on the substrate. The particles are positioned in the proximity of the visual feature and include a particle that is arranged for single photon emission in response to a suitable excitation. The method also includes characterising photon emission from the particles to identify the single photon emission and thereby identifying an approximate location of the particle arranged for single photon emission relative to the visual feature. Further, the method includes imaging the visual feature and an area in the proximity of the visual feature and thereby imaging the particle arranged for single photon emission.

Abstract: The present disclosure provides a method of forming a single photon emission system and a single photon emission system. The method comprises providing a single photon source arranged for single photon emission at a predetermined wavelength in response to a suitable excitation. The single photon source comprises a particle for generating the single photons. The method also comprises providing an optical pump source arranged to provide the suitable excitation in the form of suitable photons. In addition, the method comprises adjusting a pathway of the photons provided by the optical pump source and a position of the single photon source relative to each other so that the single photon source is located at a predetermined location relative to the pathway of the photons provided by the optical pump source and in use single photons are emitted by the single photon source.