Researchers at the University of Gothenburg have announced an interesting invention: the “smallest on-chip motor in history.”
Surprisingly, this tiny motor is so small that it can fit “inside a strand of hair.”
The incredibly small motors use light-powered gears to overcome a decades-long barrier in micromachine development.
Gears are a vital part of various technologies like clocks, cars, robots, and even wind turbines. Engineers have been attempting to make the next generation of gears as the machines are becoming smaller.
For more than 30 years, the push to create smaller gears for micro-engines had stalled at a size of 0.1 millimeters. The primary obstacle was the inability to build the necessary mechanical drive trains any smaller.
This new development, however, completely sidesteps that problem by abandoning conventional mechanics and using laser light for gear motion.
“This is a fundamentally new way of thinking about mechanics on a microscale. By replacing bulky couplings with light, we can finally overcome the size barrier,” said Gan Wang, the study’s first author, and a researcher in soft matter physics at the University of Gothenburg.
Light-driven gear
The innovative micromotor relies on advanced material science. The team manufactured silicon gears with a special optical metamaterial directly onto a microchip.
These tiny, patterned structures are designed to capture and control light on a nanoscale.
The gears were made to spin by shining a laser on the metamaterial.
The control over these tiny gears is both precise and intuitive. The laser light’s intensity directly controls the gear wheel’s speed, while its rotation direction can be changed instantly by altering the light’s polarization.
This contactless method of control is a major advantage, as it eliminates the need for any physical connections to the motor, making it highly scalable.
“We have built a gear train in which a light-driven gear sets the entire chain in motion. The gears can also convert rotation into linear motion, perform periodic movements and control microscopic mirrors to deflect light,” added Wang in the press release dated September 18.
The ability to integrate these motors directly onto a chip and power them with light opens up a vast range of possibilities.
Use in medicine
Researchers are now envisioning a future where these micro- and nanomachines can manipulate small particles, control light, or be integrated into advanced “lab-on-a-chip” systems for scientific and medical research.
The future medical devices could be made with gears as small as 16 to 20 micrometers — a size comparable to a human cell.
These tiny machines could be used as pumps or valves within the human body to regulate various flows.
“We can use the new micromotors as pumps inside the human body, for example to regulate various flows. I am also looking at how they function as valves that open and close,” Wang concluded.
However, this is just a motor prototype, and for the development to be adopted in future machines may take some years.
The findings were reported in the journal Nature Communications.