By
Techklsaini
Follow
ETH researchers have made a nanopartic turn around one billion times around their own axis. With this measurement of rotating particles, scientists are expected to gain new insights into the behavior of materials under extreme stress.
Anything in the world does not roam faster than a small particle in a laboratory at the Photonics Institute in Zurich. There, ETH professor Lucas Novotnie and his
colleagues have managed to tamper a small piece of glass in only one hundred nanometers - compared to a thousand times smaller hair - in this way it is around one billion times around its axis To make more than Scientists believe that their use will gain new insight into the stability of glass and other materials under extreme stress. The results of his research were published recently in the scientific journal Physical Review Letters.
It makes quite a lot of effort to revive the object faster. "To do this, we trap glass particles in vacuum equipment using the so-called optical tweezers," explains René Reman, a post-doc in Novoni's laboratory. Optical tweezers are made by a firmly focused laser beam, where the glass particles are taken by light forces on the focus of the beam. This allows scientists to eliminate any direct mechanical contact with the external world, which can cause friction loss. In addition, the pressure in the equipment is less than 100 million times the normal air pressure at sea level. This means that only rarely a single air molecule slows down the process of collision with particle.
Researchers now adjust the polarization of laser beams to be circular. This means that the direction in which the electric field of the laser light oscillator is not stable,
because it will be for linear polarization, but constantly rotates. In turn, that rotation is partly taken by the glass particle when the laser light passes through it. Thus the transferred torque has made the nanopartical faster and faster.
To measure rotation frequency, scientists analyze the optical tweezers laser light using a photodetector. The rotation of the glass particles has led to periodic variation in the intensity of the light passing through the particle. With this change, Novoni and his colleagues calculated that its rotation frequency was more than one gighat (one billion rotation per second). Remain acknowledged, "It's probably faster, but with our current photodetector we can not measure any high frequencies." Therefore, buying a detector faster is one of the top priorities of researchers.
With that detector, they expect to be capable of measuring rotation frequencies up to 40 GHz. However, it is likely that nanoparticles will explode before turning fast. In fact, the frequency that is very far away is obvious, because there is no reliable measure for such small things. From physical research it is known that optical glass fibers which are only a few micrometres are fat, they can withstand large tensile stress (several times of steel cables). However, nobody really knows how strong the glass particle measuring only a few nanometers is against the extreme centrifugal forces generated at high rotating frequencies that are now felt in the ETH. Those centrifugal forces can be hundred billion times bigger than the Earth's gravitational power. "This is equal to the gravitational force on the surface of the neutron star," Remain has asked to give an idea of the order of magnitude.
For nanotechnology, such measurements are important because the properties of materials in nanoscale can vary considerably from those of large objects. This is partly due to the extreme precision of nanoparticles and the virtual absence of defects. Apart from this, the measurement on the same high rotation frequencies will not be technically possible by using large objects. The challenge of nanoparticles to roam at any time, therefore, also has some practical relevance.
It is not only the rotation of the glass particle which is very fast, but there is progress in this field of research. Since some other groups were working on similar experiments, Novoni and his colleagues had to hurry up. "Eventually the data was taken in only two weeks. It was a tough end, and the whole team worked very hard to complete it," Remain recalls. Finally, the researchers were rewarded with a new record
Techklsaini
Follow
ETH researchers have made a nanopartic turn around one billion times around their own axis. With this measurement of rotating particles, scientists are expected to gain new insights into the behavior of materials under extreme stress.
Anything in the world does not roam faster than a small particle in a laboratory at the Photonics Institute in Zurich. There, ETH professor Lucas Novotnie and his
colleagues have managed to tamper a small piece of glass in only one hundred nanometers - compared to a thousand times smaller hair - in this way it is around one billion times around its axis To make more than Scientists believe that their use will gain new insight into the stability of glass and other materials under extreme stress. The results of his research were published recently in the scientific journal Physical Review Letters.
It makes quite a lot of effort to revive the object faster. "To do this, we trap glass particles in vacuum equipment using the so-called optical tweezers," explains René Reman, a post-doc in Novoni's laboratory. Optical tweezers are made by a firmly focused laser beam, where the glass particles are taken by light forces on the focus of the beam. This allows scientists to eliminate any direct mechanical contact with the external world, which can cause friction loss. In addition, the pressure in the equipment is less than 100 million times the normal air pressure at sea level. This means that only rarely a single air molecule slows down the process of collision with particle.
Researchers now adjust the polarization of laser beams to be circular. This means that the direction in which the electric field of the laser light oscillator is not stable,
because it will be for linear polarization, but constantly rotates. In turn, that rotation is partly taken by the glass particle when the laser light passes through it. Thus the transferred torque has made the nanopartical faster and faster.
To measure rotation frequency, scientists analyze the optical tweezers laser light using a photodetector. The rotation of the glass particles has led to periodic variation in the intensity of the light passing through the particle. With this change, Novoni and his colleagues calculated that its rotation frequency was more than one gighat (one billion rotation per second). Remain acknowledged, "It's probably faster, but with our current photodetector we can not measure any high frequencies." Therefore, buying a detector faster is one of the top priorities of researchers.
With that detector, they expect to be capable of measuring rotation frequencies up to 40 GHz. However, it is likely that nanoparticles will explode before turning fast. In fact, the frequency that is very far away is obvious, because there is no reliable measure for such small things. From physical research it is known that optical glass fibers which are only a few micrometres are fat, they can withstand large tensile stress (several times of steel cables). However, nobody really knows how strong the glass particle measuring only a few nanometers is against the extreme centrifugal forces generated at high rotating frequencies that are now felt in the ETH. Those centrifugal forces can be hundred billion times bigger than the Earth's gravitational power. "This is equal to the gravitational force on the surface of the neutron star," Remain has asked to give an idea of the order of magnitude.
For nanotechnology, such measurements are important because the properties of materials in nanoscale can vary considerably from those of large objects. This is partly due to the extreme precision of nanoparticles and the virtual absence of defects. Apart from this, the measurement on the same high rotation frequencies will not be technically possible by using large objects. The challenge of nanoparticles to roam at any time, therefore, also has some practical relevance.
It is not only the rotation of the glass particle which is very fast, but there is progress in this field of research. Since some other groups were working on similar experiments, Novoni and his colleagues had to hurry up. "Eventually the data was taken in only two weeks. It was a tough end, and the whole team worked very hard to complete it," Remain recalls. Finally, the researchers were rewarded with a new record
No comments:
Post a Comment