Nonlinear Metasurface Optics and Harmonic Generation

Nonlinear metasurfaces are ultrathin assemblies of engineered nano-elements that combine material nonlinearity with resonant photonic design to achieve efficient frequency conversion and wavefront control at subwavelength scales. By harnessing second- and third-order susceptibilities, these platforms enable harmonic generation, dynamic beam steering and holographic imaging without the bulk and phase-matching constraints of traditional crystals. Advances in plasmonic and dielectric meta-atom design, the incorporation of bound states in the continuum and the exploitation of geometric phases have collectively enhanced conversion efficiencies, enabled multiplexed channels in different polarisation and wavelength bands, and opened the door to compact on-chip light sources, secure optical data storage and quantum-optical interfaces. Integrating novel materials such as ferroelectrics, semiconductor heterostructures and two-dimensional transition-metal dichalcogenides has further expanded the accessible frequency range from terahertz to visible, offering tunable nonlinearity and ultrafast modulation for next-generation photonic devices.

Research from Nature Portfolio

Recent studies have demonstrated three-dimensional super-pixel holograms in nonlinear crystals, where nanometre-scale χ(2) domains are inscribed by femtosecond laser writing. Each domain encodes both amplitude and phase of the second-harmonic field, achieving pixel densities above 25000 PPI and enabling frequency-upconverted near-infrared imaging for high-capacity optical information processing. Foundational work on spin- and wavelength-multiplexed metasurface holography introduced geometric meta-atoms that imprint Pancharatnam–Berry phase profiles onto both fundamental and harmonic orders. This approach generates independent, nondispersive holographic channels with minimal crosstalk, paving the way for multidimensional optical data storage, encryption and anti-counterfeiting in ultrathin devices.

Nonlinear Metasurface Optics and Harmonic Generation publication trend

The graph below shows the total number of articles in nonlinear metasurface optics and harmonic generation across all publications each year (not limited to Nature Index journals).

Technical terms

Metasurface: A two-dimensional array of subwavelength nanostructures engineered to manipulate amplitude, phase and polarisation of light.

Harmonic generation: A nonlinear optical process converting photons at a fundamental frequency into photons at integer multiples of that frequency.

χ(2) nonlinearity: Second-order susceptibility enabling processes such as second-harmonic and sum-frequency generation.

Phase matching: Condition in which interacting waves maintain a fixed phase difference to maximise nonlinear conversion efficiency.

Pancharatnam–Berry phase: Geometric phase acquired by light through cyclic changes in polarisation, used for subwavelength wavefront shaping.

References

1. Laser nanoprinting of 3D nonlinear holograms beyond 25000 pixels-per-inch for inter-wavelength-band information processing. Nature Communications (2023).
2. Spin and wavelength multiplexed nonlinear metasurface holography. Nature Communications (2016).
3. A universal route to efficient non-linear response via Thomson scattering in linear solids. National Science Review (2023).
4. Nonlinear chiral metaphotonics: a perspective. Advanced Photonics (2023).
5. Structuring Nonlinear Wavefront Emitted from Monolayer Transition-Metal Dichalcogenides. Research (2020).