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Characterization of $NV^{-}$ centers in diamond materials and their application in microscopy and temperature sensing

Book - Dissertation

In recent years the nitrogen-vacancy (NV) center in diamond has emerged as anatom-like system with many applications in precision measurements, quantuminformation processing and quantum fundamental research. In this thesis we focuson characterization of NV centers as a function of optical excitation as well as localtemperature sensing.In order to demonstrate the significant potential the NV centers has for fun-damental scientific research as well as for technological applications, a deep un-derstanding of NV−defect centers, especially at various optical excitations is stillmissing. In this thesis several factors that affect the ODMR signal of NV−centerssuch as the power of the microwave radiation sources, magnetic field strength,optical excitation intensity and the detection efficiency of the optical system areexplored. The spectroscopy method used for these experiments is called opticallydetected magnetic resonance (ODMR). The experiments are performed to mea-sure the contrast characteristics of NV−centers under various optical excitationintensities on different types of samples and the results are backed by the energylevel simulation model for estimating population distribution between energy levels.These observations and the model provided good understanding of the contrastanalysis in NV center imaging at various optical excitations and a basis for im-proving NV−detection. Later by using the knowledge from the experiments themethod is applied to map the nanodiamonds seeded in the neuron cell culture bythe proposed background free imaging technique reported in the chapter 3.To understand the generic features of the contrast of NV−centers at variousoptical excitation intensities, experiments are performed on the multiple singlecrystal samples and the findings are reported in the chapter 4.Temperature detection properties of NV−centers are studied in chapter 5.A new method, called as frequency-jump method is introduced to detect localtemperature change on the desired surface. The method is tested first on singlecrystal diamond sample and later tested on nanodiamonds. Finally this techniqueis applied on real world problem of measuring local temperature change in a GaAs/AlAs microelectronics device, by dropcasting nanodiamonds on the devicesurface. The local heat change due to applied power to the device is measuredat different spots on the device resulting to the local temperature detection atmultiple points on the same device. The temperature sensing is measured as atime-dependent process, this in result provided the information about temperaturechange at different spots as a function of time.
Number of pages: 128
Publication year:2020
Keywords:Doctoral thesis
Accessibility:Open