According to the report on the website of British New Scientist weekly on August 22, using plasma to make lasers can make them more powerful and compact.
Matthew Edwards and Pierre Michel of Lawrence Livermore National Laboratory in California, USA, proposed a laser design that includes components made of plasma. Plasma is a state of matter, similar to the hot "soup" of charged particles. They calculated that since the plasma can reflect and focus very strong light without damaging itself, using it can help build a laser thousands of times more powerful than the most powerful laser available.
Edwards said: "we want lasers that can provide very strong light, so that we can conduct a lot of fresh and interesting physics research. The problem is that as lasers generate more and more energy, they tend to self destruct. But we can apply more light to the plasma, from 100 times to 1 million times, without damaging it."
The researchers have built a mathematical model of the laser, in which one component, the transmission grating, will be made by emitting a smaller laser into the gas to create a special pattern of plasma, instead of being made of a gold-plated glass material, such as silicon dioxide, as usual. Like the traditional laser, the lens and mirror will help to generate a beam of light, but the beam will be transformed into a very fast and intense light pulse through the plasma grating.
Edwards said that the power and size of the laser depends on the ability of the components in the device to withstand the beam intensity without collapse.
The researchers have built a mathematical model of the laser, in which one component, the transmission grating, will be made by emitting a smaller laser into the gas to create a special pattern of plasma, instead of being made of a gold-plated glass material, such as silicon dioxide, as usual. Like the traditional laser, the lens and mirror will help to generate a beam of light, but the beam will be transformed into a very fast and intense light pulse through the plasma grating.
Edwards said that the power and size of the laser depends on the ability of the components in the device to withstand the beam intensity without collapse.
The most powerful laser at present requires a meter level transmission grating, and it can output tens of petwatts of power in a millionth of a second. If it lasts for one hour, it will consume more than twice as much energy as the U.S. power grid per hour. Edwards said that the plasma grating of the plasma laser is only 1.5 mm in diameter, but it can produce an equally powerful beam. With larger gratings, unprecedented laser power can be created.
David Turnbull of the University of Rochester in New York said that the new design was eye-catching, but controlling and limiting the plasma in the device was an engineering challenge. However, he said, this design provides an opportunity to push forward the front of laser power and intensity, even to the extent that it is possible to "tear" the vacuum into particle and antiparticle pairs with very powerful laser pulses.
Edwards said that although some plasma gratings have been produced in the experiment, it may take more than a few years to produce a complete laser using a plasma grating. In the short term, the goal of the researchers is to test their design by making a laser that is smaller but as powerful as the existing high-intensity laser.
Source: reference information network
