Refraction between isotropic media is characterized by light bending towards the normal to the boundary when passing from a low- to a high-refractive-index medium. However, refraction between anisotropic media is a more exotic phenomenon which remains barely investigated, particularly at the nanoscale. Here, we visualize and comprehensively study the general case of refraction of electromagnetic waves between two strongly anisotropic (hyperbolic) media, and we do it with the use of nanoscale-confined polaritons in a natural medium: α-MoO. The refracted polaritons exhibit non-intuitive directions of propagation as they traverse planar nanoprisms, enabling to unveil an exotic optical effect: bending-free refraction. Furthermore, we develop an in-plane refractive hyperlens, yielding foci as small as λ/6, being λ the polariton wavelength (λ/50 compared to the wavelength of free-space light). Our results set the grounds for planar nano-optics in strongly anisotropic media, with potential for effective control of the flow of energy at the nanoscale.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8282686 | PMC |
http://dx.doi.org/10.1038/s41467-021-24599-3 | DOI Listing |
In this paper the finite-difference time-domain general vector auxiliary differential equation method [Opt. Express14, 8305 (2006)10.1364/OE.
View Article and Find Full Text PDFJ Nanobiotechnology
January 2025
State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200438, China.
Background: Intraoperative imaging is critical for achieving precise cancer resection. Among available techniques, Raman spectral imaging emerges as a promising modality due to its high spatial resolution and signal stability. However, its clinical application for in vivo imaging is limited by the inherently weak Raman scattering signal.
View Article and Find Full Text PDFACS Nano
January 2025
Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
Understanding energy transport in semiconductors is critical for the design of electronic and optoelectronic devices. Semiconductor material properties, such as charge carrier mobility or diffusion length, are commonly measured in bulk crystals and determined using models that describe transport behavior in homogeneous media, where structural boundary effects are minimal. However, most emerging semiconductors exhibit nano- and microscale heterogeneity.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Institute for Pulsed Power and Microwave Technology IHM, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Estimating the effective permittivity of anisotropic fibrous media is critical for advancing electromagnetic applications, requiring detailed microstructural and orientation analyses. This study introduces innovative approaches for disclosing the orientation and microstructure of fibers, leading to mixing relations. It particularly focuses on two specific fiber configurations: 1.
View Article and Find Full Text PDFNanoscale Adv
January 2025
Department of Modern Mechanical Engineering, Waseda University 3-4-1 Ookubo Shinhuku-ku Tokyo Japan
The diffusion motions of individual polymer aggregates in disordered porous media were visualized using the single-particle tracking (SPT) method because the motions inside porous media play important roles in various fields of science and engineering. In the aggregates diffused on the surfaces of pores, continuous adsorption and desorption processes were observed. The relationship between the size of the aggregates and pore size was analysed based on diffusion coefficients, moment scaling spectrum (MSS) slope analysis, and diffusion anisotropy analysis.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!