Dynamically manipulating third-harmonic generation of phase change material with gap-plasmon resonators.

Area of Science:

• * Photonics and Nanotechnology
• * Nonlinear Optics

Background:

• * Third-harmonic generation (THG) is a key nonlinear optical process.
• * Enhancing THG efficiency in nanoscale devices is crucial for practical applications.
• * Phase-change materials offer tunable optical properties.

Purpose of the Study:

• * To theoretically demonstrate a dynamic THG device.
• * To enhance THG efficiency using plasmonic resonators and phase-change materials.
• * To enable dynamic switching of THG signals.

Main Methods:

• * Incorporation of chalcogenide phase change material (Ge$_{2}$Sb$_{2}$Te$_{5}$) into ultra-small gap-plasmon resonator cavities.
• * Coupling plasmonic resonances to enhance electromagnetic fields.
• * Tuning the phase states of Ge$_{2}$Sb$_{2}$Te$_{5}$ between amorphous and crystalline.

Main Results:

• * Achieved up to a five-order magnitude increase in THG efficiency.
• * Demonstrated dynamic switching of THG signals by altering the phase state of Ge$_{2}$Sb$_{2}$Te$_{5}$.
• * Significantly enhanced electromagnetic fields within ultra-small cavities.

Conclusions:

• * The proposed dynamic THG nanostructures offer significant efficiency enhancements.
• * The ability to dynamically switch THG signals is demonstrated.
• * This work is beneficial for developing advanced dynamic nonlinear nanophotonic devices.