Electrically tunable third-harmonic generation using intersubband polaritonic metasurfaces

Area of Science:

• Optics and Photonics
• Materials Science
• Quantum Engineering

Background:

• Nonlinear optical metasurfaces offer efficient frequency conversion and beam manipulation.
• Electrical modulation of nonlinear responses is crucial for advanced optical devices.
• Intersubband transitions in multiple quantum wells (MQWs) provide giant nonlinear responses.

Purpose of the Study:

• To experimentally demonstrate electrical modulation of mid-infrared third-harmonic generation (THG) using intersubband polaritonic metasurfaces.
• To investigate the Stark tuning of resonant intersubband nonlinearity for controlling nonlinear optical responses.
• To achieve dynamic beam steering and phase tuning in nonlinear optical elements.

Main Methods:

• Fabrication of intersubband polaritonic metasurfaces based on MQWs.
• Utilizing plasmonic nanoresonators integrated with MQWs.
• Applying Stark tuning to modulate the intersubband nonlinearity.
• Experimental measurement of third-harmonic generation (THG) signals and diffraction tuning.

Main Results:

• Achieved 450% modulation depth of the THG signal.
• Demonstrated 86% suppression of zero-order THG diffraction.
• Exceeded 180 degrees of local phase tuning.
• Successfully steered THG beams using phase gradients.

Conclusions:

• First experimental implementation of electrical modulation for mid-infrared THG using intersubband polaritonic metasurfaces.
• Demonstrated versatile functionalities including efficient frequency conversion, dynamic beam manipulation, and electrical tunability.
• Presents a novel pathway for developing electrically tunable flat nonlinear optical elements.