A tiny optical chip has emerged that could greatly reduce the burden of laser control, which has been cited as a key challenge in scaling up quantum computers.

TechRadar reported on April 22 that the chip, about the size of a grain of salt, uses a structure that controls more targets more quickly with fewer beams of light. It could reduce equipment and power burdens in large-scale quantum systems.

The technology was developed under the Quantum Moonshot project of MITRE, a U.S. nonprofit research and development organisation. Participants include MITRE, the Massachusetts Institute of Technology, the University of Colorado Boulder and Sandia National Laboratories. The project aims to create a scalable quantum computing architecture that can stably handle large-scale qubits by combining light-based control technology with solid-state materials.

Using lasers to control qubits in quantum computers has clear limits in scalability. If the number of qubits grows to the millions, the existing method of controlling each with an individual laser leads to an exponential increase in equipment and control complexity. To address this, the researchers chose an approach that rapidly repositions a small number of laser beams across many target points.

The disclosed chip is about 1 square millimetre in size. Inside is an array of microscopic cantilevers, and each structure acts as an inclined surface that changes the path of light. When voltage is applied, an aluminium nitride layer in the structure expands or contracts, moving the cantilever. In the process, light travelling along an optical waveguide is precisely scanned to various points on a two-dimensional surface.

Performance is also sharply improved compared with existing technology. IEEE Spectrum reported the chip can scan about 68.6 million light spots per second, more than 50 times faster than micromirror-based beam scanners. The researchers said this is close to the physically possible diffraction limit.

In a technology demonstration, the team succeeded in creating a precise image in an extremely small area. A representative example was an experiment that reproduced the Mona Lisa image within a space smaller than two human eggs. Still, in the actual implementation, precisely controlling the movements of thousands of microstructures simultaneously was cited as a bigger challenge than manufacturing the hardware.

Its applications are not limited to quantum computers. The researchers see the same scanning technology as able to greatly increase the speed of laser-based manufacturing processes, particularly 3D printing. They also presented a forecast that processes that previously took hours could be shortened to minutes. They also mentioned potential expansion into imaging, high-performance computing and bio-laboratory equipment, among other fields.

The researchers are also reviewing a method of reshaping the cantilever structure into a spiral. This could be used in lab-on-a-chip systems that induce or measure chemical reactions using light at the cell level.

The technology is still at the experimental stage. Even so, if a structure that controls many points with a small number of light sources is commercialised, it could lead to simpler equipment and lower power consumption not only in quantum computers but across data centres. Whether it can be applied to real systems and whether it will lead to changes in the design of large-scale computing infrastructure are expected to be key points to watch.