Extending laser ablation beyond the microscopic scale could benefit scientific and space applications
Researchers have developed a method of pulling macroscopic objects using laser light. Optical tractor beams in microscopes have been demonstrated before, but this is one of the first examples of laser pull being used on larger objects.
Light contains both energy and momentum and can be used for various types of light manipulation such as levitation and rotation. For example, optical tweezers are commonly used scientific instruments that use laser light to hold and manipulate small objects such as atoms and cells. Over the past decade, scientists have been working on new types of optical manipulation. Use laser light to create an optical tractor beam that can pull objects.
“In previous studies, the light-pulling force was too small to pull macroscopic objects,” said Lei Wang, a research team member at Qingdao University of Science and Technology in China. “With our new approach, the amplitude of the force that pulls light is much higher. is also three orders of magnitude larger.”
In the journal Optica Publishing Group Optics ExpressWang et al.2 The composite object they designed can be used for laser ablation in noble gas environments. In this type of environment, the atmospheric pressure is much lower than atmospheric pressure.
“Our technology offers a non-contact, long-range pulling approach that could be useful for a variety of scientific experiments,” said Wang. “The lean gas environment we used to demonstrate this technology is similar to those found on Mars, so it may one day be possible to operate vehicles and aircraft on Mars.”
generate enough power
In a new study, researchers engineered a special graphene-SiO2 Composite structure dedicated to laser drawing. When illuminated by a laser, the structure produces an inverse temperature difference. That is, the side farther from the laser gets hotter.
An object made of graphene-SiO2 When a laser beam hits the composite structure, the back side of the gas molecules receives more energy and pushes the object towards the light source. Combining this with the low atmospheric pressure of the noble gas environment allowed researchers to obtain laser traction powerful enough to move macroscopic objects.
Using a torsion (or rotation) pendulum device made from graphene-SiO2 With the composite structure, the researchers demonstrated the laser attraction phenomenon in a macroscopic manner. We then quantitatively measured the force pulling the laser using a conventional gravitational pendulum. Both devices were approximately 5 cm long.
Repeatable and adjustable pull
“We found that the pulling force was more than three orders of magnitude greater than the light pressure,” says Wang. “Furthermore, the laser extraction is reproducible and the force can be tuned by changing the laser power.”
The researchers warn that the work is only a proof of concept and that many aspects of the technology need to be improved before it becomes practical. A systematic theoretical model is required to accurately predict the pulling force of a laser for specific parameters. They also want to improve their laser pull strategy so that it works with a wider range of air pressures.
“Our work shows that flexible optical manipulation of macroscopic objects is feasible if the interactions between light, matter and medium are carefully controlled,” said Wang. I’m here. “It also illustrates the complexity of laser-matter interactions and shows that many phenomena are not understood at both macro- and microscales.”
Original: Researchers create an optical tractor beam that pulls macroscopic objects
Than: Qingdao University of Science and Technology
