Thousands of microscopic ski jumps are launching light off a silicon sliver, turning a long-standing integration bottleneck into a projector smaller than a grain of salt.
An MIT-led consortium describes in Nature a photonic chip whose surface buckles into thousands of curved “ski-jump” emitters. Each curl is a bimaterial strip: silicon-nitride and aluminum-nitride layers cool at different rates after deposition, so the free end lifts like a thermostat coil until it points several micrometres above the wafer. On-chip waveguides feed light to these curved mirrors, which steer it into free space without external lenses.
“On a chip, light travels in wires, but in our normal, free-space world, light travels wherever it wants. Interfacing between these two worlds has long been a challenge. But now, with this new platform, we can create thousands of individually controllable laser beams that can interact with the world outside the chip in a single shot,” says Henry Wen, the MIT/Mitre co-lead.
Full-colour test images roughly half the size of a table-salt grain were projected. Wen notes that, were the same area tiled with smartphone pixels, the density would approach 30.000 pixels; this is a theoretical comparison, not a demonstrated display.
Rapid on-chip modulators switch beams without active error correction because, the authors report, the optical pattern “stays perfectly still on its own.”
Beyond imaging, the platform steered laser light onto diamond-based qubits, a step the Quantum Moonshot Program—MIT, University of Colorado Boulder, Mitre, and Sandia—views as necessary for wiring millions of qubits. So far only a handful of qubits have been addressed, and the work remains a proof of concept.
Yield, uniformity, and emitter lifetime have yet to be quantified. If those metrics improve, the authors suggest the chips could underpin high-resolution AR glasses, compact Lidar for micro-robots, faster laser-based 3-D printers, or large-scale quantum computers.
Source: MIT