Photonic structures and techniques for enhanced measurement of spin qubits in diamond

• Main Author: Hadden, J. P.
• Published: University of Bristol 2013
• Subjects: 537.6
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.664971

The negatively charged nitrogen vacancy centre is a promising candidate for use as a single photon source for linear optical quantum information, and as a solid state spin for solid state quantum information and room temperature magnetometry. However low photon collection efficiency is a problem for each of these applications. We demonstrate how photon losses due to refraction can be eliminated through the use of Solid Immersion Lenses (SILs) nano-fabricated on the surface of diamond. Coherent electron spin manipulation and readout is demonstrated on NV- centres under SILs. We show initial investigations into the effects of FIB fabrication on the NV- centre's coherence time, and demonstrate unitary quantum process discrimination on between two non orthogonal processes. In order to improve collection efficiency further it is necessary to couple NV- centres to optical micro cavities. This requires a higher degree of precision in the measurement of the NV- centres position than is possible using conventional confocal microscopy. We investigate spectral self interferometric microscopy as a method for precision measurement of the depth of an NV- centre. Finally we show coherent manipulation of photons emitted from a near infra-red colour centre in diamond using a single integrated waveguide chip. This is used to verify wave particle duality of the photons.