ナノテクノロジー革命には標準化された「ネジ」が必要 – その測定方法がここにある(The nanotechnological revolution requires standardised ‘screws’ – here is a way to measure them)

ad

2024-06-17 バース大学

バース大学の物理学者を中心とした国際チームが、光が微小な粒子を通過するときに照明とは異なる色で散乱されるという新しい非線形光学特性を発見しました。この現象は「二次高調波散乱」と呼ばれ、照明光の2倍の周波数で発生します。この特性は、ディスプレイ技術、化学触媒、医療など多岐にわたる分野に重要な影響を与えます。研究では、ウイルスや細菌のような微粒子が白色光で青く見える「チンダル現象」を調査しました。また、シリコンヘリックスを用いた実験で、これらの粒子がキラリティ(分子のねじれ方向)を示すことを発見し、今後のナノテクノロジー材料の組み立てに応用できる可能性が示されました。

<関連情報>

シリコン・ナノへリックスからのチロプティック第二高調波チンダル散乱 Chiroptical Second-Harmonic Tyndall Scattering from Silicon Nanohelices

Ben J. Olohan, Emilija Petronijevic, Ufuk Kilic, Shawn Wimer, Matthew Hilfiker, Mathias Schubert, Christos Argyropoulos, Eva Schubert, Samuel R. Clowes, G. Dan Pantoş, David L. Andrews, and Ventsislav K. Valev
ACS Nano  Published:June 17, 2024
DOI:https://doi.org/10.1021/acsnano.4c02006

Abstract

ナノテクノロジー革命には標準化された「ネジ」が必要 – その測定方法がここにある(The nanotechnological revolution requires standardised ‘screws’ – here is a way to measure them)

Chirality is omnipresent in the living world. As biomimetic nanotechnology and self-assembly advance, they too need chirality. Accordingly, there is a pressing need to develop general methods to characterize chiral building blocks at the nanoscale in liquids such as water─the medium of life. Here, we demonstrate the chiroptical second-harmonic Tyndall scattering effect. The effect was observed in Si nanohelices, an example of a high-refractive-index dielectric nanomaterial. For three wavelengths of illumination, we observe a clear difference in the second-harmonic scattered light that depends on the chirality of the nanohelices and the handedness of circularly polarized light. Importantly, we provide a theoretical analysis that explains the origin of the effect and its direction dependence, resulting from different specific contributions of “electric dipole–magnetic dipole” and “electric dipole–electric quadrupole” coupling tensors. Using numerical simulations, we narrow down the number of such terms to 8 in forward scattering and to a single one in right-angled scattering. For chiral scatterers such as high-refractive-index dielectric nanoparticles, our findings expand the Tyndall scattering regime to nonlinear optics. Moreover, our theory can be broadened and adapted to further classes where such scattering has already been observed or is yet to be observed.

1700応用理学一般
ad
ad
Follow
ad
タイトルとURLをコピーしました