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Published on: August 5, 2020
Thickness-dependent second-harmonic generation and electric-field modulation in layered GaSe and InSe
Ke Zhang1,2, Haoran Mu3, Yanqiu Xue1
1Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, P. R. China. lingshenghuang@sslab.org.cn.
Nanoscale
|July 20, 2026
Summary
Layered GaSe and InSe materials show strong nonlinear optical properties, enabling electrically tunable photonics. Their second-harmonic generation is thickness-dependent and can be modulated by electric fields, paving the way for advanced photonic devices.
Area of Science:
- Materials Science
- Photonics
- Condensed Matter Physics
Background:
- Two-dimensional van der Waals layered materials offer unique nonlinear optical properties.
- Layered III-VI semiconductors like GaSe and InSe exhibit strong second-order nonlinearity.
- Electrical tunability is crucial for integrated nonlinear photonics.
Purpose of the Study:
- Investigate thickness-dependent second-harmonic generation (SHG) in GaSe and InSe.
- Explore electric-field modulation of nonlinear optical properties.
- Assess the potential for electrically tunable photonic devices.
Main Methods:
- Second-harmonic generation (SHG) measurements on layered GaSe and InSe.
- Thickness-dependent optical characterization.
- Field-effect transistor (FET) device fabrication for electrical modulation.
- Evanescent-field-coupled optical transmission experiments in fiber-integrated structures.
Main Results:
- SHG intensity scales nonlinearly with material thickness.
- Effective second-order nonlinear susceptibility measured up to ~31.1 pm V-1.
- Electrically tunable SHG achieved with >20% modulation depth.
- Reversible electro-optic modulation demonstrated in fiber-integrated devices.
Conclusions:
- Layered GaSe and InSe are promising materials for nonlinear photonics.
- Electrical tuning of nonlinear optical responses is feasible.
- These materials hold potential for integrated, tunable photonic technologies.
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