Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Electric Dipoles and Dipole Moment

Electric Dipoles and Dipole Moment

Consider two charges of equal magnitude but opposite signs. If they cannot be separated by an external electric field, the system is called a permanent dipole. For example, the water molecule is a dipole, making it a good solvent.
Theoretically, studying electric dipoles leads to understanding why the resultant electric forces around us are weak. Since electric forces are strong, remnant net charges are rare. Hence, the interaction between dipoles helps us understand electrical interactions in...

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...

Induced Electric Dipoles

Induced Electric Dipoles

A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Creating stable trapping force and switchable optical torque with tunable phase of light.

Science advances·2022

Same author

Rapidly and accurately shaping the intensity and phase of light for optical nano-manipulation.

Nanoscale advances·2022

Same author

Optical trapping and manipulation for single-particle spectroscopy and microscopy.

The Journal of chemical physics·2022

Same author

Plasmonic SERS Biosensor Based on Multibranched Gold Nanoparticles Embedded in Polydimethylsiloxane for Quantification of Hematin in Human Erythrocytes.

Analytical chemistry·2020

Same author

Optical Sorting at the Single-Particle Level with Single-Nanometer Precision Using Coordinated Intensity and Phase Gradient Forces.

ACS nano·2020

Same author

Phase Transition and Self-Stabilization of Light-Mediated Metal Nanoparticle Assemblies.

ACS nano·2020

Same journal

Monolithic Axial InGaAs Quantum Dot Emitters in GaAs-Based Nanowires via Sb-Mediated Facet Engineering.

Nano letters·2026

Same journal

Electrical Imaging of DNA Substructures Using Quasi-Static Nanopore Scanning.

Nano letters·2026

Same journal

Structural Basis of Hemoglobin Amyloid Fibrils Revealed by cryo-EM and Molecular Dynamics Simulations.

Nano letters·2026

Same journal

Rashba-Related Spin-Selective Effect in 2D Chiral Perovskites with Achiral Organic Cation Spacers.

Nano letters·2026

Same journal

Visualizing Superconducting Gap Modulation Induced by Pair-Breaking Scattering Interference in Bulk FeSe.

Nano letters·2026

Same journal

Generalized Geometric Phase for Coupled Meta-Atoms.

Nano letters·2026

See all related articles

Search research articles

Related Experiment Video

Updated: Aug 26, 2025

Optical Trapping of Nanoparticles

Optical Trapping of Nanoparticles

Published on: January 15, 2013

Stable Negative Optical Torque in Optically Bound Nanoparticle Dimers.

Tailei Qi¹, Fei Han¹, Wenbo Liu¹

¹Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.

|October 3, 2022

Summary

This summary is machine-generated.

Researchers demonstrated stable negative optical torque in nanoparticle dimers by increasing particle size. This finding extends negative torque phenomena to smaller optical matter systems and offers new avenues for light-driven nanomotor development.

Keywords:

Negative optical torque light−matter interaction nanoparticle optical binding self-assembly

More Related Videos

Direct Force Measurements of Subcellular Mechanics in Confinement using Optical Tweezers

Direct Force Measurements of Subcellular Mechanics in Confinement using Optical Tweezers

Published on: August 31, 2021

Label-free Single Molecule Detection Using Microtoroid Optical Resonators

Label-free Single Molecule Detection Using Microtoroid Optical Resonators

Published on: December 29, 2015

Related Experiment Videos

Last Updated: Aug 26, 2025

Optical Trapping of Nanoparticles

Optical Trapping of Nanoparticles

Published on: January 15, 2013

Direct Force Measurements of Subcellular Mechanics in Confinement using Optical Tweezers

Direct Force Measurements of Subcellular Mechanics in Confinement using Optical Tweezers

Published on: August 31, 2021

Label-free Single Molecule Detection Using Microtoroid Optical Resonators

Label-free Single Molecule Detection Using Microtoroid Optical Resonators

Published on: December 29, 2015

Area of Science:

Optomechanics
Nanophotonics
Soft Matter Physics

Background:

Negative optical torque is an optomechanical effect observed in nanoparticle clusters (optical matter) under circular polarization.
Previous experimental limitations restricted stable negative torque to optical matter comprising three or more nanoparticles.

Purpose of the Study:

To investigate the reversal of optical torque sign in nanoparticle dimers by increasing particle size.
To demonstrate the emergence of stable negative torque in smaller-scale optical matter systems.

Main Methods:

Utilized computational analysis to study optical torque in nanoparticle dimers.
Investigated the role of multipolar resonances in larger nanoparticles (300 nm Au, 490 nm polystyrene).

Main Results:

Achieved stable negative optical torque in nanoparticle dimers by increasing particle size.
Observed negative torque in dimers of 300 nm diameter gold and 490 nm diameter polystyrene nanoparticles.
Computational analysis linked enhanced forward scattering along spin angular momentum to negative torque via momentum conservation.

Conclusions:

Stable negative optical torque can be achieved in nanoparticle dimers, reducing the minimum size for this phenomenon.
The findings demonstrate the universal nature of negative torque in optical matter systems.
The underlying principles offer novel strategies for designing light-driven nanomotors.