Broadband giant nonlinear response using electrically tunable polaritonic metasurfaces.

Area of Science:

• Nonlinear optics
• Metasurfaces
• Semiconductor heterostructures

Background:

• Intersubband transitions in semiconductor heterostructures enable tunable nonlinear optical responses.
• Nonlinear polaritonic metasurfaces couple intersubband nonlinearities with nanocavity modes for enhanced frequency mixing.
• Current limitations include static spectral responses of nanocavities, restricting tunability.

Purpose of the Study:

• To overcome spectral limitations of nonlinear metasurfaces.
• To achieve broadband and electrically tunable nonlinear optical responses.
• To demonstrate a novel nonlinear polaritonic metasurface design.

Main Methods:

• Quantum-engineered semiconductor heterostructures with Stark tunable nonlinearities.
• Arrays of three nanocavities with distinct resonant wavelengths.
• Experimental demonstration of broadband second harmonic generation (SHG).

Main Results:

• Broadband giant nonlinear response achieved.
• Electrically tunable SHG with peak efficiency shifted across 8.9-10.6 μm range via bias voltage.
• Demonstrated dynamic control over nonlinear optical properties.

Conclusions:

• The developed nonlinear polaritonic metasurfaces offer a promising route for broadband and electrically tunable nonlinearities.
• This approach enables dynamic control over optical properties in metasurfaces.
• Potential applications in tunable optical signal processing and free-space optics.