Invention of gears smaller than a hair, powered by light

Swedish scientists have created tiny gears powered by laser light, so small they can fit inside a human hair.

Light-powered micro-gears could revolutionize medicine - Photo: Gan Wang

Researchers at the University of Gothenburg (Sweden) have successfully created microscopic gears powered by laser light. This achievement opens up the possibility of creating the tiniest motors ever, small enough to fit inside a strand of hair and even operating at the scale of a human cell.

In a publication in Science News , the team said they designed gears that are just 0.016 mm in diameter, smaller than the average diameter of a human hair.

Previously, gear miniaturization was limited to 0.1 mm in size because it was impossible to make mechanical drives small enough to operate. However, Gothenburg researchers have broken this barrier by replacing traditional drives with… laser light.

The gears are made of silicon, printed directly onto the microchip using photolithography technology, then coated with a layer of "optical metamaterials", nanostructures that can capture and control light. When a laser is shined on them, the gears start to rotate. The intensity of the light determines the speed, while changing the polarization of the laser allows the direction of rotation to be adjusted.

This means researchers are getting closer to creating "micro-engines" that run on light.

“We have built a transmission system in which light-powered gears can drive a chain of gears. They can also convert rotational motion into translational motion, create periodic motion, or control micromirrors to bend light,” said Dr. Gan Wang, lead author of the study.

The advantage of this method, he said, is that it is possible to directly integrate tiny machines onto the chip and control them using only light, without physical contact. That makes it easy to scale up to more complex micromechanical systems.

“This is a completely new way of thinking about mechanics at the microscopic scale. By replacing bulky joints with light, we have overcome the size barrier,” he emphasized.

As the gears can be as small as 16-20 micrometers, which is the size of many human cells, the potential for medical applications becomes extremely wide open. Gan Wang envisions these light engines acting as tiny pumps in the body, helping to regulate micro-flows, or becoming microscopic valves capable of opening and closing precisely.

In addition to medicine, this technology can also be applied in "lab-on-a-chip" systems, controlling light, manipulating microscopic particles or developing new generation optical devices.

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MINH HAI

Source: https://tuoitre.vn/phat-minh-banh-rang-nho-hon-soi-toc-chay-bang-anh-sang-20250921235938555.htm