Enhancement of the Third Harmonic Generation Efficiency of ITO nanolayers coupled to Tamm Plasmon Polaritons

TL;DR

This paper demonstrates that coupling ITO nanolayers to Tamm plasmon polaritons significantly enhances third harmonic generation efficiency, with potential applications in nonlinear photonics.

Contribution

It introduces a novel TPP-ENZ platform that achieves 8x enhancement of THG in ITO nanolayers, combining experimental and numerical analysis.

Findings

8x enhancement of third harmonic generation

Dependence of THG on incident angle and orientation

Numerical simulations support experimental results

Abstract

We study the enhancement of third harmonic generation in indium tin oxide nanolayers coupled to Tamm plasmon polaritons (TPPs). The TPPs are excited at the interface between a thin gold mirror and a silicon dioxide/silicon nitride (SiO2/Si3N4) distributed Bragg reflector with a 30nm-thick indium tin oxide (ITO) nanolayer embedded inside the topmost dielectric layer under the metal mirror. This ITO nanolayer exhibits epsilon-near-zero (ENZ) behavior at near infrared wavelengths. By tuning the angle of incidence and the TPP resonance conditions, we achieve sub-wavelength confinement of the electromagnetic field, resulting in a 8x enhancement of the nonlinear optical response of the structure compared to the isolated ITO nanolayer at its optimal ENZ condition. We further investigate the dependence of the THG signal on the incident angle and sample orientation, confirming that the enhancement is driven by the excitation of the TPP mode with a characteristic asymmetric behavior. Numerical simulations of local field factors based on the transfer matrix method (TMM) fully support our findings. Our study demonstrates that the TPP-ENZ platform offers a versatile and highly efficient approach to enhancing nonlinear optical processes, with potential applications in frequency conversion, optical signal processing, and the development of more efficient nonlinear photonic devices.