40 citations · 53 across the 7 of their papers we have counts for
11 papers
Low-field dephasing time of an optically polarized NV spin bath beyond the P1 limit in diamond: a cluster-correlation-expansion and exact spin-bath study
Chikara Shinei
Dense ensembles of nitrogen-vacancy (NV) centres in nitrogen-rich diamond dephase on the electron spins of the substitutional nitrogen (P1) centres. If the paramagnetic nitroge…
Robust Diamond Quantum Sensing in Double-Quantum 4-Ramsey Interferometry by Dual-Feedback Scheme
Yuta Araki, Takeharu Sekiguchi, Yuji Hatano +11
We developed a highly sensitive and long-term stable diamond quantum magnetometer by integrating a dual-feedback system that compensates for common- and differential-mode frequency…
Semiclassical spin-bath calculation of the nitrogen-isotope effect on NV ensemble coherence in diamond
Chikara Shinei
The ratio / of the Hahn-echo and Ramsey times of nitrogen-vacancy (NV) ensembles is independent of the nitrogen concentration [N] and is 16 in diamond of…
Theoretical study of nitrogen-vacancy spin coherence enhanced by vacancy aggregation in diamond using cluster-correlation expansion
Chikara Shinei
Annealing a semiconductor makes its vacancies mobile; they aggregate into multi-vacancy complexes that often carry spin. Such centres are a magnetic-noise source for any spin qubit…
Vacancy-mediated nitrogen diffusion and aggregation via high-fluence electron beam irradiation in HPHT synthesized diamond crystal
Chikara Shinei, Yuta Masuyama, Jun Chen +5
The negatively charged nitrogen vacancy (NV-) center in diamond is a promising point defect for highly sensitive quantum sensing. The formation of high-density NV- centers is essen…
A Highly Sensitive Diamond NV Magnetometer Using Ramsey Interferometry with a Short Sensor-to-Sample Distance
Yuta Araki, Takeharu Sekiguchi, Yuji Hatano +11
In this study, we developed a diamond quantum magnetometer based on Ramsey interferometry with a short sensor-to-sample distance. Conventional biomagnetic sensors with ensemble nit…
Multichannel highly sensitive diamond quantum magnetometer
Atsumi Yoshimura, Ayumi Kanamoto, Naota Sekiguchi +9
We demonstrate a highly sensitive real-time magnetometry method at two measurement points. This magnetometry method is based on the frequency-division multiplexing of continuous-wa…
Performance Evaluation of a Diamond Quantum Magnetometer for Biomagnetic Sensing: A Phantom Study
Naota Sekiguchi, Yuta Kainuma, Motofumi Fushimi +10
We employ a dry-type phantom to evaluate the performance of a diamond quantum magnetometer with a high sensitivity of about from the viewpoint of practica…
Diamond quantum magnetometer with dc sensitivity of < 10 pT Hz toward measurement of biomagnetic field
N. Sekiguchi, M. Fushimi, A. Yoshimura +10
We present a sensitive diamond quantum sensor with a magnetic field sensitivity of in a near-dc frequency range of 5 to 100~Hz. This sensor is b…
Long Rayleigh length confocal microscope: A fast evaluation tool for obtaining quantum properties of color centers
Yuta Masuyama, Chikara Shinei, Shuya Ishii +4
Color centers in wide band-gap semiconductors, which have superior quantum properties even at room temperature and atmospheric pressure, have been actively applied to quantum sensi…
Millimetre-scale magnetocardiography of living rats using a solid-state quantum sensor
Keigo Arai, Akihiro Kuwahata, Daisuke Nishitani +16
A key challenge in cardiology is the non-invasive imaging of electric current propagation occurring in the cardiovascular system at an intra-cardiac scale. A promising approach for…