All-optical polarization tuning based on an intensity-dependent nonlinear metasurface

Active control of light polarization at the nanoscale is essential for integrated photonic devices. Here, an all-optical approach is proposed to tune the polarization state of near-infrared light using a nonlinear metasurface. Based on the large intensity-dependent refractive index change of epsilon-near-zero (ENZ) materials, a phase difference between two orthogonal electric fields at ENZ wavelength can be continuously tuned in a range larger than 0.61 pi by varying the incident light power. The polarization state of the reflected light can thus be actively tuned from linear to circular state via an all-optical approach. Notably, abundant polarization states can be obtained by altering the polarization angle of incident light. The proposed all-optical approach is promising for tunable photonic functionalities of practical applications.

Automated summary

An all-optical approach is proposed to actively control the polarization state of near-infrared light at the nanoscale using a nonlinear metasurface. By exploiting the intense refractive index change of epsilon-near-zero (ENZ) materials, the phase difference between two orthogonal electric fields at ENZ wavelength can be continuously tuned by varying the incident light power. This allows the polarization state of the reflected light to be actively tuned from linear to circular state. The proposed all-optical approach holds promise for tunable photonic functionalities in practical applications.