Physicists at the University of Washington used a laser as a liquid cooler
Welcome to the iCover Blog Pages ! In the view of many, a laser is just a source of concentrated thermal energy. Physicists from the University of Washington, who have demonstrated a laser that can be used as a liquid cooler in real conditions, are trying to dispel this misconception. About what result the specialists managed to achieve and what prospects, according to the group, breaks the proposed method, we will tell in our today's publication.
The vast majority of the unprepared audience perceives the laser beam as a directed source of thermal energy, which can perfectly cope with the role of a working tool, a means of intimidating the enemy or used, for example, as a surgical tool. It is more difficult to imagine that a concentrated laser beam with certain radiation parameters under certain conditions can not only cut and incinerate, but also cool it. The fact that a similar effect can be reproduced not only in a vacuum, but also in water or in another liquid, was proved in their experiments by a group of physicists from the University of Washington under the leadership of Peter J. Pauzauskie , assistant professor of materials science and engineering at the university.
During the experiment, scientists used a laser that forms radiation in the infrared part of the spectrum. Water was poured inside the setup chamber and a nanocrystal used as a target and suspended in water was placed. As a result of irradiation with a laser beam, the microscopic crystal began to emit. The specificity of the experiment was that the energy emitted by the nanocrystal emitted by the nanocrystal exceeded the absorbed photon energy of the infrared laser radiation, which forced the crystal to compensate for the energy deficit due to the energy of the thermal motion of the atoms. The crystal was cooled, while cooling the water around it. The result of the experiment was a decrease in water temperature to 2.2ºC ( 36ºF ).
In order to accurately determine that the water is cooling precisely around the “target”, the instruments recorded the position of the shadow of the suspended nanocrystal. With heat loss, the target slowed down near the capture point in the optical trap. By tracking the amplitude of the micromotions of the nanocrystal, scientists were able to conclude that it is cooling. The fact that the crystal was cooled was also confirmed by a color change - from bluish-green - to reddish-green.
At the next stage of the experiment, the laser created by the engineers was able to cool the biological solution used as a medium for growing cells in molecular and genetic laboratory experiments using the same principle.
The choice in favor of infrared radiation, the authors of the experiment explain, is not accidental, since one of the possible applied goals in the case of successful testing of the method should be biological objects (The radiation of the infrared spectrum, in contrast to the visible, does not cause a cell burn).
In a press release, researchers list many potential promising uses for their proposed laser cooling technology. In microelectronics, for example, such a beam could be used for point cooling of components of computer chips, which would prevent them from overheating and increase computing performance.
In biology, directed dosed cooling could be in demand to lower the temperature of part of the dividing cell in order to study the chromosome changes that arise in this case. With decreasing temperature, the intensity of biological processes inevitably decreases, which gives scientists the opportunity to track the “retrospective” of the entire process in a convenient time period. “It is important that using the radiation in the part of the spectrum that we have proposed, you don’t have to cool the whole cell, risking to kill this tiny unit of life: it will be enough to direct the beam to the desired area,” Poizovsky notes.
According to scientists, the directed laser beam of the proposed radiation spectrum could, if necessary, cool even one neuron and, without damaging it, reduce its activity.
The production (growing) of crystals that determine the laser power, as noted in the publication, is a rather expensive process. Crystals for the lasers used in the “cooling installations” of the Poiseowski group can be obtained “... using much simpler, cheaper, more affordable and, more importantly, scalable hydrothermal synthesis technology ...”.
The limited capabilities of the group made it possible to obtain practical confirmation of the method by working with only one nanocrystal. In the future, scientists believe, the volume of experimental data will be increased through the use of several, which involves the use of lasers of greater power.
The practical capabilities of the technology are impressive, but at the same time, the issue of energy efficiency of the cooling process is rather acute. And this is one of the problems that the group has yet to work on.
“We are interested in the ideas and suggestions of other scientists or representatives of the business sphere,” says Peter Pausovsky, “to expand the field of application of laser cooling of liquids with the maximum benefit for humanity."
You can find a brief report on the results of the work done in the group’s press release on the university’s website .
PS Vacuum laser cooling technology was first demonstrated at the Los Alamos National Laboratory (LANL) in 1995.
*****
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The vast majority of the unprepared audience perceives the laser beam as a directed source of thermal energy, which can perfectly cope with the role of a working tool, a means of intimidating the enemy or used, for example, as a surgical tool. It is more difficult to imagine that a concentrated laser beam with certain radiation parameters under certain conditions can not only cut and incinerate, but also cool it. The fact that a similar effect can be reproduced not only in a vacuum, but also in water or in another liquid, was proved in their experiments by a group of physicists from the University of Washington under the leadership of Peter J. Pauzauskie , assistant professor of materials science and engineering at the university.
During the experiment, scientists used a laser that forms radiation in the infrared part of the spectrum. Water was poured inside the setup chamber and a nanocrystal used as a target and suspended in water was placed. As a result of irradiation with a laser beam, the microscopic crystal began to emit. The specificity of the experiment was that the energy emitted by the nanocrystal emitted by the nanocrystal exceeded the absorbed photon energy of the infrared laser radiation, which forced the crystal to compensate for the energy deficit due to the energy of the thermal motion of the atoms. The crystal was cooled, while cooling the water around it. The result of the experiment was a decrease in water temperature to 2.2ºC ( 36ºF ).
In order to accurately determine that the water is cooling precisely around the “target”, the instruments recorded the position of the shadow of the suspended nanocrystal. With heat loss, the target slowed down near the capture point in the optical trap. By tracking the amplitude of the micromotions of the nanocrystal, scientists were able to conclude that it is cooling. The fact that the crystal was cooled was also confirmed by a color change - from bluish-green - to reddish-green.
At the next stage of the experiment, the laser created by the engineers was able to cool the biological solution used as a medium for growing cells in molecular and genetic laboratory experiments using the same principle.
The choice in favor of infrared radiation, the authors of the experiment explain, is not accidental, since one of the possible applied goals in the case of successful testing of the method should be biological objects (The radiation of the infrared spectrum, in contrast to the visible, does not cause a cell burn).
In a press release, researchers list many potential promising uses for their proposed laser cooling technology. In microelectronics, for example, such a beam could be used for point cooling of components of computer chips, which would prevent them from overheating and increase computing performance.
In biology, directed dosed cooling could be in demand to lower the temperature of part of the dividing cell in order to study the chromosome changes that arise in this case. With decreasing temperature, the intensity of biological processes inevitably decreases, which gives scientists the opportunity to track the “retrospective” of the entire process in a convenient time period. “It is important that using the radiation in the part of the spectrum that we have proposed, you don’t have to cool the whole cell, risking to kill this tiny unit of life: it will be enough to direct the beam to the desired area,” Poizovsky notes.
According to scientists, the directed laser beam of the proposed radiation spectrum could, if necessary, cool even one neuron and, without damaging it, reduce its activity.
The production (growing) of crystals that determine the laser power, as noted in the publication, is a rather expensive process. Crystals for the lasers used in the “cooling installations” of the Poiseowski group can be obtained “... using much simpler, cheaper, more affordable and, more importantly, scalable hydrothermal synthesis technology ...”.
The limited capabilities of the group made it possible to obtain practical confirmation of the method by working with only one nanocrystal. In the future, scientists believe, the volume of experimental data will be increased through the use of several, which involves the use of lasers of greater power.
The practical capabilities of the technology are impressive, but at the same time, the issue of energy efficiency of the cooling process is rather acute. And this is one of the problems that the group has yet to work on.
“We are interested in the ideas and suggestions of other scientists or representatives of the business sphere,” says Peter Pausovsky, “to expand the field of application of laser cooling of liquids with the maximum benefit for humanity."
You can find a brief report on the results of the work done in the group’s press release on the university’s website .
PS Vacuum laser cooling technology was first demonstrated at the Los Alamos National Laboratory (LANL) in 1995.
*****
Dear readers, we are always happy to meet and wait for you on the pages of our blog. We are ready to continue to share with you the latest news, review articles and other publications and will try to do our best to make the time spent with us useful for you. And, of course, do not forget to subscribe to our columns .
Our other articles and events