A research group led by Associate Professor Kazuyasu Goto of the Faculty of Engineering has developed a novel high-pressure physical property measurement technique using dielectric metasurfaces.
Key points of this research
- We have developed a technique to measure the refractive index change of materials under high pressure by creating a meta-surface (Note 2) on the anvil of an anvil cell (Note 1) used in high-pressure experiments.
- Compared to conventional methods, this technology offers a superior balance of simplicity, high sensitivity, and robustness, and enables measurements in localized areas that were previously difficult to measure.
- This achievement will contribute to the advancement of planetary science and condensed matter physics.
overview
The development of high-pressure material property measurement techniques is crucial in fields such as planetary science and condensed matter physics. To date, a simple and highly sensitive method has been proposed that measures the refractive index change of a material inside an anvil cell by observing the color change of gold nanoparticles that become colored by surface plasmon resonance (Note 3). However, because gold nanoparticles are soft, they deform significantly above a certain pressure, leading to unexpected color changes.
A research group led by Assistant Professor Hiromasa Shinke of the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Professor Yuki Kimura of the Institute of Low Temperature Science, Hokkaido University, Professor Hiroki Nada of the Department of Mechanical and Physical Engineering, Faculty of Engineering, Tottori University, Associate Professor Tetsuya Hama of the Department of Interdisciplinary Sciences/Advanced Science Research Organization, Graduate School of Arts and Sciences, University of Tokyo, and Associate Professor Kazuyasu Goto of the Graduate School of Natural Science and Technology, Tohoku University, has focused on a phenomenon called Mie vacancy resonance (Note 4), in which vacancies change color when sub-μm vacancies are formed in dielectrics. They have proposed a new method to measure refractive index changes from the color change of Mie vacancies fabricated on the surface of a hard anvil. This method is expected to have the same level of simplicity and sensitivity as methods using metal nanoparticles, as well as higher robustness against pressure. This result is expected to contribute to the development of various scientific fields involving high pressure.
These results were published online in the scientific journal The Journal of Physical Chemistry C on November 8th (US Pacific Standard Time).
[Terminology]
(Note 1) Anvil cell:
An anvil cell is a device that generates high pressure at the tips of two pointed, rigid materials (anvils) by introducing a sample into a metal plate with small holes called a gasket and pressing the tips together firmly.
(Note 2) Metasurface:
Materials that possess properties not found in naturally occurring materials, such as those acquired through the formation of artificially created nanostructure arrays using microfabrication technology, are called metamaterials. In particular, surfaces that possess such properties by forming pseudo-two-dimensional nanostructure arrays are called metasurfaces.
(Note 3) Surface plasmon resonance:
This refers to the collective oscillation of free electrons that are excited by light irradiation on metal nanoparticles and follow the oscillations of the electric field of light.
(Note 4) Mie hole resonance:
This refers to the phenomenon in which light of a specific wavelength, determined by the size of the vacancy, selectively resonates within a sub-micrometer-sized vacancy formed in a high refractive index dielectric material.
Research details
Paper information
[Publication] The Journal of Physical Chemistry C
[Paper Title] Mie Voids for High-Pressure Refractive Index Sensing
[Authors] Hiromasa Niinomi*, Hiroki Nada, Tetsuya Hama, Kazuhiro Gotoh, Yumiko Kodama, Tomoya Oshikiri, Masaru Nakagawa, and Yuki Kimura
*Corresponding author: Hiromasa Niike, Assistant Professor, Institute of Multidisciplinary Materials Science, Tohoku University
[doi]10.1021/acs.jpcc.5c05941