Manufacturing Bits: July 24

World’s fastest rotor; controlling light; corn LiDAR.


Fast rotors
Purdue University and others have developed what researchers claim is the world’s fastest man-made rotor.

Researchers devised a tiny dumbbell from silica. Then, the object was levitated in a vacuum using a laser, thereby creating a spinning effect. This, in turn, enabled more than 60 billion revolutions per minute or more than 100,000 times faster than a dental drill.

The technology falls under the category of levitated optomechanics. Applications for this technology include the study of precision measurements, thermodynamics and quantum mechanics. Purdue, Peking University, Tsinghua University, and the Collaborative Innovation Center of Quantum Matter also contributed to the research.

Specifically, researchers developed a silica-based dumbbell that measures 170nm in diameter. Then, a laser hits the object in a straight line or in a circular fashion. If the laser is pointed in a linear fashion, the object vibrates. If the laser moves in circular fashion, the dumbbell spins.

A nanodumbbell levitated by an optical tweezer in vacuum can vibrate or spin, depending on the polarization of the incoming laser. (Purdue University photo/Tongcang Li)

In both cases, researchers typically use these techniques to explore the gravitational constant and the density of Earth. With the new technology, researchers hope to explore the properties of quantum mechanics and vacuum environments.

“This study has many applications, including material science,” said Tongcang Li, an assistant professor of physics and astronomy, and electrical and computer engineering at Purdue University, on the university’s Web site. “We can study the extreme conditions different materials can survive in.

“People say that there is nothing in vacuum, but in physics, we know it’s not really empty,” Li said. “There are a lot of virtual particles which may stay for a short time and then disappear. We want to figure out what’s really going on there, and that’s why we want to make the most sensitive torsion balance.”

Controlling light
Technion-Israel Institute of Technology has developed an optic isolator, a tiny rotating device that controls the direction and size of light signals.

The optic isolator was developed at Technion’s glass blowing workshop. Using glass blowing technology, researcher constructed a tiny glass rod. Then, the tip of the rod was melted into a 1mm-radius ball.

The ball forms the optic isolator. Then, the rod is situated in a system. The system rotates the device at a speed of 300 kph. Then, researchers took standard optical fiber. The fiber is positioned on opposite directions and several nanometers away from the device.

Optic isolator based on resonance of light waves. (Source: Technion-Israel Institute of Technology)

The, light is shined on the optic isolator from opposite directions. As it turns out, light entering on one side is blocked. Then, light entering from another side is transmitted. In other words, light entering from one side echoes inside the sphere and then is absorbed. In contrast, light entering from the opposing side is undisturbed.

Applications include quantum and optical computing. “The speed of light depends on the speed of the medium in which it is moving,” said Tal Carmon, a professor at Technion-Israel Institute of Technology. “Precisely like a swimmer in a river – the speed of light against the movement of the medium is slower than its speed with the movement of the medium.

“Essentially, we developed a very efficient photonic isolator, which can isolate 99.6% of the light,” Carmon said. “Namely, if we sent 1,000 light particles, the device will effectively isolate 996 photons and will miss only 4. Such isolation efficiency is necessary for applications that include quantum optics communication devices and building high-powered lasers. The isolator we developed here fulfills several additional requirements: it also works well when light from both opposing directions is simultaneously perceived, it is compatible with standard optical-fiber technology, it can be scaled down and it does not change the color of the light.”

Corn LiDAR
The University of Nebraska-Lincoln has accelerated the analysis of crop traits using a technology called LiDAR.

Researchers placed a corn plant on a plate. Then, they rotated the plate at three degrees per second. It moves back to its original position in two minutes.

On a separate unit, LiDAR is used to fire pulsed laser light at a surface of the corn. Then, it measures the time it takes for those pulses to reflect back. In turn, LiDAR collects millions of 3D coordinates. Then, it makes a digital rendition of the plant.

Nebraska researchers have devised a more efficient and accurate way to scan the structural properties of plants. (Source: Yufeng Ge, Suresh Thapa, Scott Schrage)

Using the technology, researchers can compare crops and look for specific genetic traits. All told, the technology could help produce more food. “We can already do DNA sequencing and genomic research very rapidly,” said Yufeng Ge, assistant professor of biological systems engineering at the University of Nebraska-Lincoln. “To use that information more effectively, you have to pair it with phenotyping data. That will allow you to go back and investigate the genetic information more closely. But that is now (reaching) a bottleneck, because we can’t do that as fast as we want at a low cost.”

Suresh Thapa, a doctoral student in biological systems engineering, added: “LiDAR is advantageous in terms of the throughput and speed and in terms of accuracy and resolution. And it’s becoming more economical (than before).”

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