This article digs into a breakthrough from researchers at the CUNY Advanced Science Research Center. They’ve built a nonlinear metasurface that not only converts infrared light to visible wavelengths, but also steers the outgoing beam—no moving parts required.
By combining efficient third-harmonic generation with programmable wavefront control in a geometry-driven metasurface, this work opens up new directions for ultra-compact, integrated photonics. It’s a development with big implications for sensing, communications, and quantum technologies.
Technology Overview
The metasurface uses a carefully designed lattice. Each unit cell has two rectangular apertures, rotated 90 degrees from each other.
This tiny, highly structured geometry lets nonlocal light-matter interactions happen across the surface. The result? Strong, collective resonances that trap and amplify incoming infrared light.
The device manages to convert color efficiently while still controlling where the emitted light goes. That’s a tricky combo to pull off.
Key design features
- Two-aperture unit cells arranged with a 90-degree rotation, enabling nonlocal coupling across the surface.
- Collective resonance that traps and amplifies infrared light over the entire metasurface, boosting third-harmonic efficiency.
- Third-harmonic generation (THG) converts 1,530 nm infrared to visible light around 510 nm (green).
- Per-pixel phase programming by rotating nanoscale blocks in a tailored pattern, imprinting a position-dependent phase on the emitted light—like a built-in lens or prism.
Operation and Functionality
The device gets excited from below by a circularly polarized pump. If you change the pump’s polarization, you can steer the direction of the emitted visible light—no mechanical parts in sight.
This combo of nonlinear frequency conversion and dynamic steering is what makes the metasurface so promising for compact photonic integration.
How the mechanism comes together
- Nonlocal interactions and collective resonance enhance the infrared field across the surface, raising THG efficiency.
- The patterned rotation of each nanoscale element imposes a position-dependent phase on the emitted light, so you get precise control over the outgoing wavefront.
- The approach couples high-efficiency delocalized resonances with pixel-level phase control, tackling a classic trade-off in metasurface design between efficiency and wavefront shaping.
- It’s all geometry-driven, so it’s not stuck with just one material. You could adapt this to other nonlinear materials and spectral ranges, even ultraviolet if you wanted.
Why This Is a Game Changer for Photonics
By fusing efficient nonlinear frequency conversion with programmable beam steering on a single, compact platform, this metasurface unlocks new capabilities for integrated photonics. The geometry-driven approach means you could extend similar functionality to different materials and wavelengths without overhauling the core mechanism.
Being able to steer a converted beam while keeping conversion efficiency high makes it a great fit for on-chip optical circuits and systems that need tight light control at the nanoscale.
Advantages and adaptability
- High efficiency from delocalized resonances and per-pixel wavefront control.
- Compact, integrated platform—ideal for on-chip photonics, LiDAR, and quantum photonics.
- Spectral flexibility with the potential to expand to ultraviolet and other nonlinear materials.
Applications and Impact
The team showed both color conversion and controlled steering in experiments, proving the platform’s practical value for integrated photonic systems. Potential uses? Think ultra-compact light sources, LiDAR for autonomous sensing, quantum light generation, and on-chip optical signal processing.
By letting one device handle both frequency conversion and beam steering, the metasurface could shrink optical architectures and reduce system footprints—while expanding what next-gen photonic circuits can actually do.
Where this technology could shine
- Ultra-compact light sources that combine generation and direction control in one element.
- LiDAR and environmental sensing with integrated, tunable beam steering.
- Quantum light generation and manipulation on chip, enabling new quantum communication and computation approaches.
- On-chip optical signal processing with streamlined frequency conversion and routing.
Here is the source article for this story: CUNY metasurface turns infrared into steerable visible light