Sensing Stress and Hyperfine Structures Using Defects in Diamond

The negatively charged nitrogen vacancy NV centre is one of the most successful solid defects in quantum sensing. Its optical properties and spin dynamics allow initialization, optical readout and spin manipulation to be done with ease. It has a long coherence time at room temperature making it superior to other solid defects in the context of sensing. NV centre is thus a promising quantum sensor, and techniques such as optically detected magnetic resonance (ODMR) measurement or pulse sequence measurement can be easily implemented. ; In this thesis, the pressure inhomogeneity and solidification of pressure medium in a diamond anvil cell (DAC) were investigated using NV in nano-diamond (ND) as a pressure sensor. The signal from NDs provided a pressure mapping of the DAC pressure chamber, which allows one to quantify the pressure inhomogeneity, to keep track of the phase transition of pressure medium and to trace the pressure evolution. Another similar study on strain sensing utilizing polymer materials is also presented here, and altogether, show that ND is an excellent stress sensor with high spatial resolution and high sensitivity. On the other hand, studies on 13C defect and P1 centre are presented. It is seen that, by using NV to sense the hyperfine interaction with 13C defect, one could derive the wavefunction of NV and its change under pressure. P1 centre is then investigated by employing various pulse measurements such as Hahn-echo and DEER sequence. These sequence measurements also give detail properties of NV itself and its surroundings in the sample, for example, coherence time and the type of defects existed nearby. ; 帶負電荷的氮空位(NV)中心是量子傳感中最成功的固體缺陷之一。它的光學特性和自旋動力學允許輕鬆完成初始化、光學讀出和自旋操作。它在室溫下具有較長的相干時間，使其在傳感方面優於其他固體缺陷。NV中心因此是一種優秀的量子傳感器，並且可以輕鬆實現諸如光學檢測磁共振或脈衝序列測量的技術。 ...