Scientists have built a macroscopic tractor beam using laser light : ScienceAlert

Scientists have built a macroscopic tractor beam using laser light : ScienceAlert
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Tractor beams make intuitive sense. Matter and energy interact with each other in myriad ways throughout the Universe. Magnetism and gravity are natural forces that can bind objects together, so there is a kind of precedent.

But designing an actual tractor beam is something different.

A tractor beam is a device that can move an object from a distance. The idea comes from a 1931 science fiction story called IPC Space Hounds:

“There’s such a thing as a beam screen, killjoy, and there’s also lift or tractor beams, two things that I’ve been trying to eliminate and have been giving me.”
The Bronx cheers me up. The Titanians have had a tractor beam for a long time (he sent me full info on it) and the Jovians have both. We’ll have them in three days, and it should also be pretty simple to equip the opposite of a tractor: a pusher or a presser beam.”

If science fiction had anything to say about it, tractor beams would be commonplace by now, and we could thank star trek Y Star Wars for its proliferation.

But tractor beams already exist, though their reach is only microscopic.

Microscopic tractor beams are used in devices called optical tweezers. Optical tweezers use lasers to move microscopic objects like atoms and nanoparticles. They are used in biology, nanotechnology and medicine.

These tractor beams work on microscopic objects, but they are not strong enough to attract larger macroscopic objects.

Now a team of researchers has successfully demonstrated a macroscopic tractor beam. They published the paper explaining their work in the magazine Express Optics. Your title is “Knudsen force-based macroscopic laser traction in rarefied gas,and the lead author is Lei Wang from the QingDao University of Science and Technology in China.

“In previous studies, the attractive force of light was too small to attract a macroscopic object.” saying wang.

“With our new approach, the pulling force of light has a much larger amplitude. In fact, it is more than three orders of magnitude greater than the pressure of light used to drive a solar sail, which uses the momentum of photons. to exert a small push force.”

A tractor beam demonstrated with green lasers.

This macroscopic tractor beam only works under particular laboratory conditions, so it is a demonstration, not a practical development. At least not yet.

First of all, it works on purpose-built stuff: macroscopic graphene-SiO2 composite objects that the researchers built for the experiments.

Second, it works in a rarefied gaseous environment, which has a much lower pressure than Earth’s atmosphere. While that limits its effectiveness here on Earth, not all worlds have as much atmospheric pressure as our planet.

“Our technique provides a long-distance, non-contact pulling approach, which can be useful for various scientific experiments.” saying wang.

“The rarefied gas environment we used to demonstrate the technique is similar to that found in Mars. So it could have the potential to one day rig vehicles or aircraft on Mars.”

Your device works on the principle of gas heating. A laser heats composite objects, but one side is hotter than the other. The gas molecules at the back receive more energy, which attracts the object. Combined with the lower pressure in the rarefied gas environment, the object moves.

The researchers built a torsion pendulum device made of their graphene-SiO2 composite structure to demonstrate the phenomenon of laser traction. That demo made it visible to the naked eye. They used another device to measure the effect.

“We found that the pulling force was more than three orders of magnitude greater than the light pressure,” saying wang. “In addition, the laser pull is repeatable and the force can be adjusted by changing the power of the laser.”

Other researchers have tractor beams boarded in recent years with mixed results. NASA was interested in pursuing the idea of ​​using tractor beams to collect samples with the MSL Curiosity surface rover. One of Curiosity’s instruments is the ChemCam.

It includes a laser that vaporizes rock or regolith and then a micro-imager to measure its components spectroscopically. But NASA wondered if a tractor beam could draw tiny particles from the vaporized sample to the rover for further study.

A NASA NIAC Presentation of 2010 said: “If Tractor Beam technology were included in a ‘ChemCam2’ to attract dust particles and plasma, tractor beams could add a suite of additional science capabilities:

  • laser desorption ion spectroscopy
  • mass spectrometry
  • raman spectroscopy
  • X-ray fluorescence”

The same presentation said that tractor beams could be used to collect particles from comet tails, ice plumes on Enceladus, and even clouds in Earth’s atmosphere or other atmospheres.

That never materialized, but it illustrates how compelling the idea is.

This new research produced interesting results, although it is nowhere near an actual practical implementation. A lot of work and engineering is needed before it gets anywhere near practicality.

On the one hand, there must be a well-understood theoretical basis that describes how the effect works on objects with different sizes and shapes and with lasers of different powers in different atmospheres.

The researchers know this, of course, but point out that it’s still an effective demonstration of feasibility.

“Our work demonstrates that flexible light manipulation of a macroscopic object is feasible when the interactions between light, object, and medium are carefully controlled.” saying wang.

“It also shows the complexity of laser-matter interactions and that many phenomena are far from being understood at both the macro and micro scales.”

The critical part is that this study moves the tractor beams from the microscopic to the macroscopic. That is a significant threshold that is difficult to cross.

“This work extends the scope of optical extraction from the microscale to the macroscale, which has great potential in macroscale optical manipulations,” the authors state. writes at its conclusion.

Spaceships may very well use tractor beams one day, but they’re unlikely to be anything like those in science fiction. Star Wars, star trekand SIPC hounds all feature tractor beams in combat and conflict.

But in reality, they could become valuable scientific tools.

This article was originally posted by universe today. Read the Original article.

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