Nonlinear Optical Phenomena in Metasurfaces

Metasurfaces are ultra-thin assemblies of subwavelength structures engineered to manipulate light at the nanoscale. When designed from materials with strong optical nonlinearity, these planar architectures can convert, modulate and steer light through processes such as harmonic generation, frequency mixing and ultrafast refractive index modulation. The localisation of electromagnetic fields within individual meta-atoms amplifies nonlinear interactions, enabling significant light-matter coupling in devices just tens to hundreds of nanometres thick. Key applications span compact frequency converters, on-chip optical modulators, quantum light sources and dynamic wavefront shapers. Advances in fabrication of dielectric and semiconductor metasurfaces have alleviated losses associated with plasmonic designs and exploited electric and magnetic Mie resonances to boost conversion efficiencies. The ability to relax phase-matching constraints in two-dimensional geometries further broadens the accessible spectral range, from ultraviolet to infrared. Collectively, these developments pave the way to highly integrated photonic systems that leverage femtosecond dynamics, high damage thresholds and tailored dispersion for next-generation communications, sensing and quantum technologies.

Research from Nature Portfolio

Recent studies have demonstrated ultrafast control of nonlinear wavefronts by integrating two-dimensional materials with dielectric metasurfaces. One approach combines a WSe₂ monolayer with a dielectric nanopattern to achieve femtosecond second-harmonic beam deflection and on-the-fly structuring of optical orbital angular momentum. This hybrid system reaches response times compatible with telecom rates while encoding information in the harmonic wavefront. Another foundational work exploits gallium arsenide nanoparticle arrays supporting magnetic and electric Mie resonances in the near infrared. By optical pumping at low fluence, researchers have achieved picosecond-scale modulation of reflectance and spectral tuning of resonance positions, enabling efficient all-optical switching. Complementing these transient studies, dielectric GaAs metasurfaces have been shown to function as broadband optical frequency mixers, simultaneously generating a spectrum of new frequencies—second, third and fourth harmonics as well as sum- and four-wave mixing processes—by harnessing intrinsic material nonlinearities and relaxed phase-matching.

Nonlinear Optical Phenomena in Metasurfaces publication trend

The graph below shows the total number of articles in nonlinear optical phenomena in metasurfaces across all publications each year (not limited to Nature Index journals).

Technical terms

Metasurface: A two-dimensional array of subwavelength structures designed to control amplitude, phase or polarization of light.

Harmonic generation: A nonlinear optical process in which incident photons at one frequency are converted into photons at integer multiples of that frequency (e.g. second- or third-harmonic).

Mie resonance: A resonance arising from the scattering of light by dielectric particles, supporting electric and magnetic modes that enhance field confinement.

Fano resonance: A spectrally narrow interference phenomenon between a discrete resonant mode and a broad continuum, often used to amplify nonlinear optical responses.

References

1. A multi-mode super-fano mechanism for enhanced third harmonic generation in silicon metasurfaces. Light: Science & Applications (2023).
2. Ultrafast all-optical second harmonic wavefront shaping. Nature Communications (2024).
3. Giant photoinduced reflectivity modulation of nonlocal resonances in silicon metasurfaces. Advanced Photonics (2023).
4. Highly Efficient Ultraviolet Third‐Harmonic Generation in an Isolated Thin Si Meta‐Structure. Advanced Science (2024).
5. Ultrafast all-optical tuning of direct-gap semiconductor metasurfaces. Nature Communications (2017).
6. An all-dielectric metasurface as a broadband optical frequency mixer. Nature Communications (2018).