Third-harmonic light polarization control in magnetically resonant silicon metasurfaces

Area of Science:

• Nanophotonics and Metasurface Engineering
• Nonlinear Optics
• Light-Matter Interactions at the Nanoscale

Background:

• Nonlinear metasurfaces offer nanoscale light control.
• Typically, only the total third harmonic polarization is analyzed.
• Diffraction orders from metasurfaces can exhibit unique polarization characteristics.

Purpose of the Study:

• To investigate the polarization states of individual diffraction orders generated by a nonlinear metasurface.
• To demonstrate the potential for controlling polarization in nonlinear light generation.
• To explore advanced wavefront control using tailored nonlinear optical responses.

Main Methods:

• Design and fabrication of a high quality factor silicon metasurface.
• Utilizing third harmonic generation as the nonlinear process.
• Employing back focal plane imaging to analyze the spatial distribution and polarization of diffraction orders.

Main Results:

• Observed a rich variety of polarization states across different diffraction orders.
• Demonstrated that polarization of generated nonlinear light can be tailored.
• Confirmed the potential for precise control over nonlinear optical phenomena at the nanoscale.

Conclusions:

• The study highlights the importance of analyzing individual diffraction orders for a complete understanding of nonlinear metasurface behavior.
• Tailoring the polarization of nonlinear diffraction orders is achievable.
• This research opens new avenues for advanced optical wavefront manipulation and nanophotonic device applications.