A highly sensitive diamond NV magnetometer using Ramsey interferometry with a short sensor-to-sample distance
Abstract
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 nitrogen-vacancy centers using continuous-wave optically detected magnetic resonance and Ramsey methods typically rely on watt-level lasers to achieve high sensitivity, resulting in thermal issues. In contrast, by employing the light-trapping diamond waveguide technique in a high-pressure and high-temperature diamond sample treated with electron beam irradiation, we obtained a high optical power conversion efficiency of 9.5%, enabling us to simultaneously achieve a high sensitivity of 2.93(7) pT/Hz in the 100–400 Hz frequency range and a minimal temperature increase of only approximately 13 K at a low laser power of 210 mW. Using a dry phantom designed to mimic magnetoencephalography signals, we measured a weak magnetic field of 77.7(2) pT without signal averaging at a sensor-to-sample distance of 2.5 mm. This short distance measurement prevents severe spatial signal attenuation, yielding a high signal-to-noise ratio. The development here is crucial for practical biomagnetic applications based on Ramsey interferometry.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (14)
Yuta Araki
Department of Electrical and Electronic Engineering, School of Engineering, Institute of Science Tokyo 1 , Meguro, Tokyo 152-8552,
Takeharu Sekiguchi
Department of Electrical and Electronic Engineering, School of Engineering, Institute of Science Tokyo 1 , Meguro, Tokyo 152-8552,
Yuji Hatano
Department of Electrical and Electronic Engineering, School of Engineering, Institute of Science Tokyo 1 , Meguro, Tokyo 152-8552,
Naota Sekiguchi
Department of Electrical and Electronic Engineering, School of Engineering, Institute of Science Tokyo 1 , Meguro, Tokyo 152-8552,
Chikara Shinei
Research Center for Electronic and Optical Materials, National Institute for Materials Science 2 , Tsukuba, Ibaraki 305-0044,
Masashi Miyakawa
Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
Takashi Taniguchi
Tokuyuki Teraji
Research Center for Electronic and Optical Materials, National Institute for Materials Science 2 , Tsukuba, Ibaraki 305-0044,
Hiroshi Abe
Shinobu Onoda
Takasaki Institute for Advanced Quantum Science, National Institutes for Quantum Science and Technology: QST 5 , Takasaki, Gunma 370-1292,
Takeshi Ohshima
Takayuki Shibata
Mutsuko Hatano
Department of Electrical and Electronic Engineering, Institute of Science Tokyo 4 , Meguro-ku, Tokyo 152-8552,
Takayuki Iwasaki
Department of Electrical and Electronic Engineering, Institute of Science Tokyo 4 , Meguro-ku, Tokyo 152-8552,