MAED made for ultra-sensitive magnetic field detection on the cellular scale
MAED made for ultra-sensitive magnetic field detection on the cellular scale lead image
Magnetic fields, electric fields, temperature, and strain can alter the photoluminescence of nitrogen vacancy (NV) centers, a type of structural imperfection in diamonds that can be used as quantum sensors. The high sensitivity of these sensors could be used to noninvasively measure magnetic fields generated by brain nerve cells to map neural activity. However, to find footing in this biological application, devices based on NV centers must be able to measure localized information about individual cells.
Kurose et al. developed an NV center-based sensor capable of detecting ultra-weak magnetic fields at the cellular scale, called the micro-NV center array element of diamond (MAED). The authors fabricated a waveguide to enhance the sensitivity of the device.
The intensity of red luminescence from NV centers changes in response to magnetic field variations, but significant dispersion of this light reduces its observable intensity and decreases a center’s magnetic field sensitivity. Recently, horizontal waveguides have been used to enhance this red emission by partially confining it. For MAED, the authors used a femtosecond Bessel beam laser to create a vertical waveguide on the diamond’s surface, which more completely confined the red light.
“Because the spatial resolution reaches the scale of individual cells, further improvement of the magnetic sensitivity may enable noninvasive measurement of brain magnetic fields, which may ultimately contribute to our understanding of neural activity,” said author Noriko Kurose. “Applications beyond cellular activity include verifying the operation of electronic devices and monitoring crustal activity by measuring geomagnetic fields, which highlight the wide versatility of this approach.”
Next, the authors will further increase the sensitivity of MAED.
Source: “Formation of two-dimensional multichannel vertical optical waveguides in an nitrogen-vacancy center diamond using a femtosecond Bessel beam laser for local quantum sensing,” by Noriko Kurose, Kotaro Obata, Shintaro Nomura, Takayo Ogawa, Satoshi Wada, Koji Sugioka, and Yoshinobu Aoyagi, Applied Physics Letters (2025). The article can be accessed at https://doi.org/10.10.1063/5.0253597 .
