World's Shortest Laser Pulse Achieved

Source:  World's Shortest Laser Pulse Achieved    Tag:  femtosecond laser pulse


A laser pulse that lasted for just 67 billionths of a billionth of a second has been created by scientists - research that will help them to witness subatomic particles move in real-time. The world record-smashing result, published in the journal Optics Express, was achieved by Dr. Zenghu Chang and colleagues at the University of Central Florida (UCF), USA, by refining a technique where short laser pulses generate even shorter ones when fired into a focused jet of inert gas. This technique allowed the team to create a laser pulse which lasted only 67 attoseconds; the former record stood at 80 attoseconds.

This process is similar to a camera with an extremely short flash but, in all actuality, is a pulse that will allow researchers to observe some of the fastest processes of the known universe. This pursuit for the shortest possible laser pulse has been going on since its first ever demonstration in 1960, with the first laser producing a pulse of an estimated thousandth of a second.

In more recent years, the stuffy of “femtosecond” lasers – pulses that last millionths of a billionth of a second – have been used as research tools for a while now – helping to examine processes like the breaking down and building up of chemical bonds. 

Yet even at these levels, there are even more layers that remain hidden in this microscopic cosmos. By moving on to attosecond science, researchers are able to examine subatomic particles inside atoms, or learn more about quantum mechanics, which is still a very mysterious world to us.

Zhengu Chang, a professor at the University of Central Florida (UCF), has now broken the record by improving a method where short laser pulses lead to even shorter ones by shooting them into inert gas contained inside a focused jet.

The pulses, while larger than a femtosecond, show a wide range of colors in various different regions, in a spectrum that is known as extreme UV. These infographs contain wavelengths far smaller than the human eyes can see. But to get it down to the record breaking status, the scientists used zinc foil and passed the pulses through it, which allows some parts of the pulse to slow down. This resulted in all the colors within the pulses to be compressed into a shorter period of time.

Speaking on the result, dean of UFC's College of Sciences, physicist Michael Johnson, said: "Dr Chang's success in making ever-shorter light pulses helps open a new door to a previously hidden world, where we can watch electrons move in atoms and molecules, and follow chemical reactions as they take place. It is astounding to imagine that we may now be able to watch quantum mechanics in process."