Related Experiment Video
Updated: Aug 6, 2026
14:52
Fabrication of Three-Dimensional Graphene-Based Polyhedrons via Origami-Like Self-Folding
Published on: September 23, 2018
Resonant Structure of Second Harmonic Generation in Multilayer Graphene Polytypes
Patrick Johansen Sarsfield1,2, Takaaki V Joya3, Takuto Kawakami3
1National Graphene Institute, University of Manchester, ManchesterM13 9PL, United Kingdom.
Nano Letters
|July 21, 2026
Summary
Second harmonic generation (SHG) reveals stacking order in multilayer graphenes (MLG). This optical technique can distinguish MLG polytypes and identify crystallographic direction noninvasively.
Area of Science:
- Optics and Photonics
- Materials Science
- Condensed Matter Physics
Background:
- Second harmonic generation (SHG) is a nonlinear optical process.
- SHG is sensitive to the broken inversion symmetry in crystalline structures.
- Multilayer graphenes (MLG) offer tunable electronic and optical properties.
Purpose of the Study:
- Analyze SHG in MLG to understand its dependence on stacking order, encapsulation, and external bias.
- Investigate SHG sensitivity to electron-hole asymmetry and doping in MLG.
- Explore SHG as a method for characterizing MLG polytypes and crystallographic orientation.
Main Methods:
- Theoretical analysis of SHG in MLG structures.
- Focus on trilayer and tetralayer MLG configurations.
- Examination of SHG spectra under varying conditions (stacking, encapsulation, doping).
Main Results:
- Identified stacking-order-dependent resonant features in SHG spectra for trilayers and tetralayers.
- Demonstrated SHG sensitivity to electron-hole asymmetry and doping.
- Showcased potential for distinguishing MLG polytypes based on SHG response.
Conclusions:
- Infrared-range SHG is a promising noninvasive technique for MLG characterization.
- SHG can differentiate between MLG polytypes.
- Optical identification of crystallographic direction in MLG films is feasible using SHG.
Related Concept Videos
02:16Resonance and Hybrid Structures
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
02:52Resonance
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O bonds.
01:03Modes of Standing Waves - I
A close look at earthquakes provides evidence for the conditions appropriate for resonance, standing waves, and constructive and destructive interference. A building may vibrate for several seconds with a driving frequency matching the building's natural frequency of vibration; this produces a resonance that results in one building collapsing while the neighboring buildings do not. Often, buildings of a certain height are devastated, while other taller buildings remain intact. This phenomenon...
03:35Hybridization of Atomic Orbitals II
sp3d and sp3d 2 Hybridization
03:24Hybridization of Atomic Orbitals I
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
01:28Standing Waves in a Cavity
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: