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Interference tunable second harmonic generation for two-dimensional materials in layered structures.

Ying Song, Weiming Wang, Yanchao Wang

|June 29, 2023

Summary

This summary is machine-generated.

We demonstrate tunable second harmonic generation (SHG) in layered 2D materials. Constructive interference between light waves maximizes SHG signals, achieving a three-order-of-magnitude enhancement in MoS2-based structures.

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Area of Science:

Materials Science
Optics
Condensed Matter Physics

Background:

Second Harmonic Generation (SHG) is a nonlinear optical process.
Two-dimensional (2D) materials offer unique optical properties.
Controlling SHG in layered structures is crucial for optoelectronic applications.

Purpose of the Study:

To experimentally investigate the tunability of SHG in a 2D material/dielectric film/substrate structure.
To understand the interference mechanisms governing SHG enhancement.
To achieve significant signal variations through structural optimization.

Main Methods:

Fabrication of a layered structure: monolayer MoS2 on TiO2 dielectric film on an Ag substrate.
Experimental measurement of SHG signals under varying conditions.
Analysis of interference effects between incident and reflected fundamental light, and between upward and downward SH light.

Main Results:

SHG tunability was observed in the 2D material layered structure.
Maximal SHG enhancement occurs when both fundamental and second harmonic interferences are constructive.
A three-order-of-magnitude variation in SHG signals was demonstrated from a monolayer MoS2/TiO2/Ag structure.
Optimal conditions involve a highly reflective substrate and a dielectric film with a significant refractive index difference.

Conclusions:

The study experimentally confirms the tunability of SHG in 2D material-based layered structures.
Interference phenomena play a critical role in modulating SHG intensity.
The findings provide a pathway for optimizing nonlinear optical responses in 2D materials for advanced photonic devices.