Scientists from the UK and South Korea have proposed a new method for generating laser pulses, which have a power more than 1000 times that of existing laser pulses.
Scientists are using computer simulations in joint research to demonstrate a new method of compressing light to fully increase its intensity, thereby extracting particles from vacuum and studying the essence of matter. To achieve this goal, these three groups jointly produced a very special mirror, which not only reflects optical pulses, but also compresses them more than two hundred times in time, and can be further compressed.
The research team from University of Strathclyde, UNIST and GIST put forward a simple idea that uses the gradient of plasma density, that is, fully ionized matter, to make photons "gather”, which is similar to a group of stretched cars gathering together when encountering a steep hill. This may completely change the next generation of lasers, increasing their power by more than one million times what can be achieved now.
A new method for compressing laser pulses in plasma has been published in Nature Photonics.
The peak power of the world's highest power laser is approximately 10 petawatts. To illustrate this, 173 petawatts of sunlight reach the upper atmosphere of Earth, among which approximately one-third reaches the Earth's surface. One petawatt is equal to 1015 watts, one exawatt 1018 watts, and a zettawatt 1021 watts. The sun generates 4 multiply 1026 watts of power or 400,000 zettawatts.
The duration of optical pulses generated by high-power lasers is very short, usually a few femtoseconds, which is achieved by using a technique called Chirped Pulse Amplification (CPA). CPA involves pulse compression, which concentrates laser pulse energy in a short time, thereby increasing its peak power by many orders of magnitude.
Professor Dino Jaroszynski of the Department of Physics of Strathclyde University said: "An important and fundamental question is what happens when the light intensity exceeds the common level on the earth.” High power lasers enable scientists to answer basic questions about the properties of matter and vacuum, and explore the so-called intensity frontier.
"The application of terawatt-petawatt lasers on matter makes it possible to develop the next generation of laser plasma-based accelerators, which are thousands of times smaller than traditional accelerators. It also provides scientists with new tools that is changing the way of scientific research. We have established the Scottish Centre for Application of Plasma-based Accelerators at University of Strathclyde to promote applications based on high-power lasers.”
Professor Min Sip Hur from UNIST said, "The results of this study have the potential to be applied in various fields, including advanced theoretical physics and astrophysics. It can also be used in laser fusion research to help tackle energy problems faced by human beings. Our joint team from South Korea and the UK plans to conduct experimental testing of these ideas in the laboratory.
Professor Hyyong Suk of GIST said, "Plasma can play a role similar to traditional diffraction gratings in CPA systems, but it is a material that does not damage. Therefore, it will enhance traditional CPA technology by including a very simple add-on. Even with a few centimeter sized plasma, it can be used for lasers with peak power exceeding one exawatt.
Exawatt and zettawatt seem to have a lot of power, and they do, but by simply using a lens or curved mirror to focus the laser pulse on a small point to concentrate its energy, its intensity can be greatly increased. Similar to compressing a laser pulse in time to a short time, by compressing the pulse in space, focusing it onto a small point, the same thing can be done in space. Therefore, compression allows for an increase in the intensity of laser pulses in a very common way - in space or time. Using a lens to focus sunlight on a piece of paper can easily test space compression; it will self ignite.
As the intensity increases, substances undergo various transformations. For example, when the intensity of air exceeds 1010 to 1012 width per square centimeter for visible light wavelengths and when electrons are subjected to lasers with an intensity higher than 10, it is 18 width per centimeter, which is close to the speed of light, leading to the field of relativistic optics.
At the above level, with an intensity of 1024 width per square centimeter, protons approach the speed of light, and particles undergoing intense laser fields react to their own radiation field, which is currently the intensity frontier in physics. When the intensity exceeds 10, it is 29 width per square centimeter, this is called the Schwinger limit, where particles are directly generated from a vacuum, that means light can be directly converted into matter. This requires a laser from exawatt to zettawatt.
One of the prominent challenges of modern physics is that understands the matter with an intensity higher than 10, and the essence of a vacuum with 24 width per square centimeter. High-power lasers can also be used for studying astrophysical phenomena in the laboratory, thus providing a unique glimpse into the interior of stars and the origin of the universe.
Source: Diodelaser net