Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Crystal Field Theory - Octahedral Complexes02:58

Crystal Field Theory - Octahedral Complexes

30.8K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
30.8K
Ionic Crystal Structures02:42

Ionic Crystal Structures

16.9K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
16.9K
Crystal Growth: Principles of Crystallization01:25

Crystal Growth: Principles of Crystallization

4.9K
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
4.9K
Crystal Field Theory - Tetrahedral and Square Planar Complexes02:46

Crystal Field Theory - Tetrahedral and Square Planar Complexes

48.3K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
48.3K
Negative Regulator Molecules01:23

Negative Regulator Molecules

38.3K
Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
38.3K
Positive, Negative, and Zero Work00:58

Positive, Negative, and Zero Work

22.1K
Work is done on an object when energy is transferred to the object. In other words, work is done when a force acts on a body that undergoes a displacement from one position to another. By definition, the work done by a force is the integral of the force with respect to the displacement along its path. Forces can vary as a function of position, and displacements can occur along various paths between two points. The magnitude of a force multiplied by the cosine of the angle that the force makes...
22.1K

You might also read

Related Articles

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

Sort by
Same author

MxDiffusion: A Physics-Aware Maxwell's Law-Guided Diffusion Model Strategy for Inverse Photonic Metasurface Design.

Nano letters·2026
Same author

A Van der Waals Material Exhibiting Room Temperature Broken Inversion Symmetry with Ferroelectricity.

Advanced science (Weinheim, Baden-Wurttemberg, Germany)·2025
Same author

Ion-Assisted Nanoscale Material Engineering in Atomic Layers.

Nano letters·2025
Same author

Determination of mid-infrared optical properties of complex media using partial Mueller matrix ellipsometry.

The Review of scientific instruments·2025
Same author

Phototransformation of achiral metasurfaces into handedness-selectable transient chiral media.

Proceedings of the National Academy of Sciences of the United States of America·2024
Same author

Determining hot-carrier transport dynamics from terahertz emission.

Science (New York, N.Y.)·2023
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

Related Experiment Video

Updated: Jan 25, 2026

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
11:08

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities

Published on: November 30, 2012

19.5K

Nonreciprocal Negative Refraction Enabled by Photonic Time Crystals.

Mohammad R Tavakol1, Wenshan Cai1,2

  • 1School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.

Nano Letters
|January 23, 2026
PubMed
Summary
This summary is machine-generated.

We demonstrate nonreciprocal negative refraction using time-varying photonic structures. This breakthrough enables isolation of light beams while preserving negative refraction, opening new possibilities for optical and microwave devices.

Keywords:
Metamaterialsnegative refractionnonreciprocityphotonic time crystalstime modulation

More Related Videos

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation
13:02

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation

Published on: February 25, 2017

10.1K
Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation
09:29

Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation

Published on: September 27, 2011

12.6K

Related Experiment Videos

Last Updated: Jan 25, 2026

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
11:08

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities

Published on: November 30, 2012

19.5K
Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation
13:02

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation

Published on: February 25, 2017

10.1K
Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation
09:29

Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation

Published on: September 27, 2011

12.6K

Area of Science:

  • Photonics and Metamaterials
  • Electromagnetism and Wave Phenomena

Background:

  • Negative refraction is a key phenomenon in metamaterials, but achieving nonreciprocity (directional control) has been challenging.
  • Time-varying photonic structures offer a novel pathway to break time-reversal symmetry and enable nonreciprocal effects.

Purpose of the Study:

  • To theoretically demonstrate nonreciprocal negative refraction using engineered time-varying photonic structures.
  • To develop practical designs for both optical and microwave frequency regimes.

Main Methods:

  • Engineering temporal modulations at the interfaces of hyperbolic media.
  • Designing multilayer hyperbolic slabs (optical) and time-modulated metasurfaces (microwave).
  • Utilizing Floquet harmonic expansions and a harmonic-balance finite-element solver for validation.

Main Results:

  • Achieved isolation between forward and backward beams while maintaining negative refraction.
  • Reported >46 dB isolation in the optical device and >11 dB in the microwave device.
  • Validated the proposed designs through theoretical analysis and numerical simulations.

Conclusions:

  • Introduced a general framework for nonreciprocal negative refraction across different frequency regimes.
  • Expanded the design space for time-varying metasurfaces and photonic time crystals.
  • Demonstrated the potential of time-varying structures for advanced optical and microwave applications.