Making waves with quantum wells and metasurfaces

In our most recent publication, we combine quantum-engineered semiconductor materials with metasurfaces to realise giant nonlinear optical responses at near-infrared wavelengths. Engineered semiconductor materials allow us to tailor their nonlinear properties through designed resonant transitions. Moving beyond the traditional use of intersubband transitions in nonlinear quantum wells, we instead engineer interband transitions to access higher photon energies and enable designs at new wavelengths.

The multi-quantum-well material, designed and grown by Seth Bank’s group at the University of Texas at Austin, offers a large intrinsic nonlinear response, but accessing it efficiently from free space remains challenging. Integrating the material with a metasurface allows us to tailor the optical fields inside the quantum wells, making the strong nonlinear response accessible from free space.

The resulting structure is less than a micrometre thick and operates at wavelengths important for telecommunications, providing a route towards compact nonlinear optical components for communications, signal processing and quantum photonics.

See the publication in Nature Nanotechnology, or check out the press release from Harvard SEAS. You can also read more about the multi-quantum-well material in a related publication from our collaborators in Optica.

Artistic rendering by Joshua Mornhinweg.