Many people first saw "ultrashort" will have on its misunderstanding. Super well understood, but short, many people tend to interpret it as "the length of the distance," but in fact, where the "short" is the length of time.
High-power laser States is coveted because it is too much in fact competent, such as military fans known laser weapons, as well as creating artificial conditions required for controlled nuclear fusion and so on.
Costing billions of dollars in US fuel pellets "NIF" use, they use 192 laser emitting simultaneously and struck a pencil-sized fuel pellets within a billionth of a second time, causing fusion.
However, high-power laser is not so easy to produce, not to say a laser device to provide energy to the greater, the greater the power of the laser. Clearly, simply provide large energy to further increase the power of the laser has now become difficult, the cost is more expensive.
How to do?
We know that: Power = work / time = w / t
Since the breakthrough in the "work" on the already very expensive and difficult, then we have from the "time" to break up.
Obviously, the same power, acting shorter the time, the greater the power. When the time tends to infinity hours, the power will tend to infinity.
1 watt (power) = 1 joule / 1 second.
For 1 joule of energy, if we put laser pulse time from 1 second shortened to 0.1 seconds, then we get 10 watts of power.
If you shorten 0.001 seconds from 1 seconds, we get 1000 watts of power.
Similarly, if reduced to 1 picosecond it? Then we got 1,000,000,000,000 watts of power (one trillion watts).
For the general public, one trillion watts of power is already as large as incredible. However, ultrashort laser pulses create our country, and in the femtosecond time scale level, the power ratio above 1 trillion watt 3 0 even more, reaching 1,000 terawatt level.
I believe, laser research industry insiders say "femtosecond" Every day, "attosecond" definitely more than the number of times a lot of people say "second" the number even more, to this end, we will start with a table to ponder about the amount of time each day level:
Our produce is laser pulses in the femtosecond time is short to the level of the corresponding laser is also called a "femtosecond laser." 1,000,000,000,000,000 watt is equal to 1 Petawatt (PW), Shanghai Institute of Optics and Fine Mechanics Institute (hereinafter referred to as the Shanghai-ray machines) laser device, the power to shoot up to 5 watts.
It can generate a lot of extreme conditions
Ultrashort laser power is so great that it can produce a lot of extreme conditions, and these conditions only inside stars or black holes can produce edge.
Ultrashort laser at present can reach 3 × 1010 joules / cm, which is equivalent to the explosion of 20 tons of TNT in a small volume of one cubic centimeter.
Super light pressure
Light creates pressure, which is the light pressure, also called radiation pressure. Science fiction is still in the "solar sail" is as a driving force. Light pressure generated by the sun's very small, but the light pressure of ultrashort laser-produced close to the atmospheric one trillion times.
What are its applications?
Ultrashort laser-produced these extreme conditions is very useful. In fact, just think you can understand that countries particle accelerators, including costly, found the God particle European Large Hadron Collider, their purpose is to create a variety of extreme energy particles, particle acceleration force and touch, so take this to explore the mysteries of the universe.
The ultrashort laser can produce so many extreme conditions, then the application of course is very extensive.
For example, ultrashort laser can produce powerful electric field, electric field can use this accelerated particles, and now, with a laser particle acceleration experiments, either internationally or our Shanghai-ray machines, etc., are under way. If the experiment next breakthrough, the ultrashort laser will make the future a variety of miniaturized linear accelerator, while reducing costs.
The Shanghai Institute of Optics and Fine Mechanics also produced the antimatter positrons is, what use is it?
As we all know, only when the photons reflected from the leaves and into our eyes, we can see a piece of leaf. And after a lot of important materials needed for aerospace, which is produced, or used in the future, we would like to understand its internal microstructure, defects, status and other information, but can not destroy the material itself, how to get? Of course, we have to use non-destructive detection.
The ultrashort laser can be made out of antimatter within the material, which is a large number of positrons, which positrons and electrons annihilation within the material, so whole mass of the electron is converted into electromagnetic radiation, and gamma photon emission detection these photons, we will indirectly detect the internal situation of the material. Positron annihilation technique can be internal material defects and damage to the atomic scale probed.
Above, only two ultrashort laser applications in the future, maybe we'll find more than just two small application only. According to the Shanghai-ray machine director Ru new researcher in "2015 International Lightyear report," in 2020, in the field of ultrashort laser, may achieve the following dream: producing a light beam and applied to nanoscale microscopy and storage; laser-based ultra-precision clock for measuring the fundamental constants of the universe; laser fusion for a larger breakthrough, human access to clean big step towards sustainable energy; developing from a femtosecond laser to attosecond laser (attosecond pulses), and thereby detecting the movement of electrons and chemical reactions.
Undoubtedly, ultrashort laser applications will be very wide, as an analysis of US academic journal article, "Science" pointed out that "This work will affect each study, from astrophysics to fusion."