Related Experiment Video
Updated: Sep 9, 2025
08:48
Demonstration of Spin-Multiplexed and Direction-Multiplexed All-Dielectric Visible Metaholograms
Published on: September 25, 2020
5.8K
Resonant Helical Dichroism in Twisted Dielectric Metastructures
Yiyuan Wang1,2,3, Chi Li4, Haoyi Yu4
1Key Laboratory of In-Fiber Integrated Optics of Ministry of Education, College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, China.
ACS Nano
|August 28, 2025
Summary
Researchers developed resonant helical dichroism (HD) using twisted silicon metastructures. This breakthrough enables stronger probing of chiral molecules and photonic structures with structured light beams.
Area of Science:
- Optics and Photonics
- Materials Science
- Nanotechnology
Background:
- Circular dichroism (CD) is vital for molecular characterization using light's spin angular momentum.
- Helical dichroism (HD) utilizes orbital angular momentum (OAM) of light for chiral structure analysis.
- Previous HD studies were nonresonant, limiting their application.
Purpose of the Study:
- To explore resonant helical dichroism (HD) in chiral nanostructures.
- To design and implement novel dielectric metastructures for enhanced HD.
- To investigate the interaction of structured light beams with OAM with these metastructures.
Main Methods:
- Fabrication of twisted dielectric metastructures using rotated silicon trimers.
- Harnessing nonlocal photonic modes with high-quality factors.
- Experimental demonstration of resonant HD with focused OAM beams (topological charges 1-3).
Main Results:
- Achieved strong resonant HD for OAM values up to 10.
- Demonstrated resonantly enhanced HD with focused OAM beams.
- Validated the performance of silicon trimer nanostructures.
Conclusions:
- Resonant HD is realized in twisted dielectric metastructures.
- These metastructures enable strong control of structured OAM beams.
- Potential applications include molecular sensing, optical imaging, and data storage.
Related Concept Videos
01:31Dielectric Polarization in a Capacitor
5.0K
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...
5.0K
02:52Stereoisomerism
12.4K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
12.4K
02:30Chirality in Nature
13.8K
Chirality is the most intriguing yet essential facet of nature, governing life’s biochemical processes and precision. It can be observed from a snail shell pattern in a macroscopic world to an amino acid, the minutest building block of life. Most of the snails around the world have right-coiled shells because of the intrinsic chirality in their genes. All the amino acids present in the human body exist in an enantiomerically pure state, except for glycine - the sole achiral amino acid.
13.8K
01:12Double Resonance Techniques: Overview
288
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
288
02:25Chirality
25.2K
Chirality is a term that describes the lack of mirror symmetry in an object. In other words, chiral objects cannot be superposed on their mirror images. For example, our feet are chiral, as the mirror image of the left foot, the right foot, cannot be superposed on the left foot.
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
25.2K
01:28Standing Waves in a Cavity
1.0K
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
1.0K