Related Experiment Video
Updated: Jan 25, 2026
04:57
Residue-Free Fabrication of van der Waals Heterostructures of Two-Dimensional Materials
Published on: July 18, 2025
1.0K
Tunable Modal Birefringence in a Low-Loss Van Der Waals Waveguide
Debo Hu1, Ke Chen1, Xinzhong Chen2
1Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China.
Advanced Materials (Deerfield Beach, Fla.)
|May 11, 2019
Summary
Elliptic van der Waals (vdW) crystals like molybdenum disulfide (MoS2) offer tunable optical properties for phase retardation. This study demonstrates low-loss light transmission and controllable birefringence in MoS2 microcrystals.
Area of Science:
- Optoelectronics
- Materials Science
- Photonics
Background:
- Van der Waals (vdW) crystals exhibit large optical birefringence, making them suitable for phase retardation.
- Hyperbolic vdW crystals are limited by lossy, transverse-magnetic (TM) polarized modes.
- Elliptic vdW crystals, such as molybdenum disulfide (MoS2), offer superior potential for optical applications.
Purpose of the Study:
- To investigate the potential of elliptic vdW crystals, specifically MoS2, for integrated phase retardation.
- To demonstrate low-loss guided mode propagation in MoS2 microcrystals.
- To explore the tunability of modal birefringence in MoS2 for controlling light polarization.
Main Methods:
- Utilized nano-optical imaging at near-infrared (NIR) wavelengths (1530 nm).
- Performed theoretical calculations to analyze modal properties.
- Investigated the effect of MoS2 microcrystal thickness on optical birefringence.
Main Results:
- Achieved low-loss transmission of both transverse-electric (TE) and TM polarized waveguide modes in MoS2.
- Demonstrated that modal birefringence is tunable in sign and magnitude by varying MoS2 thickness.
- Confirmed the suitability of MoS2 for optical communication frequencies.
Conclusions:
- MoS2 microcrystals are promising for integrated phase retardation applications.
- Tunable modal birefringence in MoS2 provides a new method for controlling photon polarization.
- Elliptic vdW crystals offer significant advantages over hyperbolic types for optical retardation.
Related Concept Videos
01:24Van der Waals Interactions
70.9K
Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive interactions between particles with permanent, partial, or temporary charges. The intermolecular forces between neutral atoms and molecules are ion–dipole, dipole–dipole, and dispersion forces, collectively known as van der Waals forces.
70.9K
01:10Van der Waals Equation
6.2K
The ideal gas law is an approximation that works well at high temperatures and low pressures. The van der Waals equation of state (named after the Dutch physicist Johannes van der Waals, 1837−1923) improves it by considering two factors.
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
6.2K
04:01Real Gases: Effects of Intermolecular Forces and Molecular Volume Deriving Van der Waals Equation
38.9K
Thus far, the ideal gas law, PV = nRT, has been applied to a variety of different types of problems, ranging from reaction stoichiometry and empirical and molecular formula problems to determining the density and molar mass of a gas. However, the behavior of a gas is often non-ideal, meaning that the observed relationships between its pressure, volume, and temperature are not accurately described by the gas laws.
38.9K
02:35Noncovalent Attractions in Biomolecules
64.3K
Noncovalent attractions are associations within and between molecules that influence the shape and structural stability of complexes. These interactions differ from covalent bonding in that they do not involve sharing of electrons.
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...
64.3K
01:15Van de Graaff Generator
2.4K
Van de Graaff generators (or Van de Graaffs) are devices used to demonstrate high voltage due to static electricity that can also be used for research. Robert Van de Graaff first built one in 1931 (based on original suggestions by Lord Kelvin) for use in nuclear physics research.
Van de Graaff uses both smooth and pointed surfaces, conductors, and insulators to generate large static charges and, hence, large voltages. A substantial excess charge can be deposited on the sphere because it moves...
Van de Graaff uses both smooth and pointed surfaces, conductors, and insulators to generate large static charges and, hence, large voltages. A substantial excess charge can be deposited on the sphere because it moves...
2.4K
01:10Line Loss
518
The different configurations of source-load connections include wye (star) and delta connections. The relationship between line and phase voltages and currents varies depending on the configuration. When the source is supplying power, it is transmitted through the wires to the load, and during this transmission, some power is absorbed by the wires, leading to line loss.
Line loss impacts power delivery efficiency in a balanced three-phase circuit. The symmetry in such a circuit simplifies the...
Line loss impacts power delivery efficiency in a balanced three-phase circuit. The symmetry in such a circuit simplifies the...
518