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Shumpei Ohyama

Publications and source records attributed to Shumpei Ohyama.

2 recordsLinked to original sources

Wide-field NV magnetometry under simultaneous high-pressure and high-temperature conditions

We demonstrate wide-field optically detected magnetic resonance (ODMR) under simultaneous high-pressure and high-temperature conditions using nitrogen-vacancy (NV) centers. Although NV-center magnetometry has been widely used for spatially resolved magnetic-field imaging, its application to extreme environments combining pressure and temperature remains challenging. In this work, we show that ODMR can be observed at 5 GPa and 500 K, demonstrating the feasibility of NV spin readout under such combined extreme conditions. We further perform wide-field ODMR of iron at 7 GPa and 500 K, where the stray magnetic field from the sample is spatially visualized through the pressure cell. These results establish NV-center magnetometry as a promising platform for imaging magnetic phenomena in materials under high-pressure and high-temperature environments.

physics.app-ph

Coherent control of solid-state defect spins via patterned boron-doped diamond circuit

Monolithic integration, which refers to the incorporation of all device functionalities within a single material, shows significant potential for creating scalable solid-state quantum devices. This study demonstrated the coherent control of nitrogen-vacancy (NV) spins using an electronic circuit monolithically integrated within diamond: a patterned, conductive boron-doped diamond (BDD) microwave waveguide. First, we validated the high-frequency performance of the circuit by characterizing its impedance up to the microwave range, confirming its capability for efficient microwave transmission. Then, using this monolithically integrated BDD--NV hybrid system, we performed optically detected magnetic resonance and observed noticeable Rabi oscillations driven by the metallic BDD circuit. Importantly, we verified that the BDD antenna has a minimal detrimental impact on the NV spins; microwave-induced heating is negligible under both pulsed and continuous driving, and the spin relaxation time ($T_1$) remains unperturbed. This approach paves the way for a new class of compact, robust, and versatile quantum platforms suitable for sensing and information processing in various environments.

physics.app-ph