ORCID Profile
0000-0001-7295-4514
Current Organisation
Toyohashi University of Technology
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Publisher: Wiley
Date: 12-04-2022
DOI: 10.1002/TEE.23613
Abstract: Virus detection methods based on the nonlinear magnetic response of magnetic nanoparticles have been investigated, and magnetic detection methods using the third harmonic have been widely applied on account of their high sensitivity, short measurement‐time, and low cost. In this letter, we propose a virus detection method using the second harmonics to improve the signal intensity. We find that the signal to noise ratio of the second harmonic is approximately three times higher than that of the third harmonic. A comparison of the ratio of the second harmonic to the fourth harmonic ( R 24 ) and the ratio of the third harmonic to the fifth harmonic ( R 35 ) shows that R 24 is more sensitive to identifying changes in virus concentration. Our proposed method has the potential to be utilized for rapid screening on virus detection. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.
Publisher: AIP Publishing
Date: 02-2023
DOI: 10.1063/9.0000483
Abstract: Virus detection methods based on nonlinear magnetic response of magnetic nanoparticles have been investigated, and magnetic detection methods using the third harmonic are widely applied, owing to their high sensitivity and short measurement time. This paper proposes a virus detection method based on the second harmonic because of its larger signal component. We found that the second harmonic signal is superior to the third harmonic signal for small nanobeads and a large change of the second harmonic signal in the signal-to-noise ratio (SNR) with nanobeads concentration. In addition, a virus detection limit of 100 pg/ml is achieved. Therefore, the proposed method can potentially be utilized for rapid screening of viruses.
Publisher: Walter de Gruyter GmbH
Date: 28-09-2020
Abstract: Laser threshold magnetometry using the negatively charged nitrogen-vacancy (NV − ) centre in diamond as a gain medium has been proposed as a technique to dramatically enhance the sensitivity of room-temperature magnetometry. We experimentally explore a diamond-loaded open tunable fibre-cavity system as a potential contender for the realisation of lasing with NV − centres. We observe lification of the transmission of a cavity-resonant seed laser at 721 nm when the cavity is pumped at 532 nm and attribute this to stimulated emission. Changes in the intensity of spontaneously emitted photons accompany the lification, and a qualitative model including stimulated emission and ionisation dynamics of the NV − centre captures the dynamics in the experiment very well. These results highlight important considerations in the realisation of an NV − laser in diamond.
No related grants have been discovered for Takashi Yatsui.