Scientists Made a Breakthrough With Laser Pulses of One Quadrillionth of a Second

And it could enhance ultra-precise surgical lasers.
Chris Young

A team of researchers from the Universities of Bayreuth and Constance revealed they can control intervals between ultrashort light flashes of a quadrillionth of a second, a press release reveals.

Light flashes shorter than a quadrillionth of a second are also known as femtosecond pulses. They are used for research into energy materials as well as for 3D manufacturing, and precision scalpels in medicine for eye and heart surgery, amongst other applications that require incredible precision. 

'Coupled' laser beams

When a laser produces ultrashort light beams, it often produces them in pairs. In a similar fashion to bonded atoms in a molecule, these pulses are "coupled" and they exhibit short temporal intervals with remarkable stability.

In an interview with Popular Sciencestudy author Georg Herink from Bayreuth University said "many people who work with these lasers know that this happens, but they thought it might be a strange curiosity. Companies try to avoid this operation mode. They just want to have a single clean pulse."

The team of German scientists, however, aimed to control the coupling to learn more about the phenomena. In order to do so, they built a ring out of optical glass fibers like the ones used to provide high-speed internet connections. Then they started shooting pulses of laser light through the ring in orbits. Using advanced high-resolution real-time spectroscopy, the scientists tracked the intervals in two coupled flashes in real-time over hundreds of orbits.

Unraveling the mystery of femtosecond pulses

In their findings, published in the journal Optica, the scientists from Bayreuth and Constance reveal that they could control the coupling. By reducing the laser's power for a short time period, they were able to break the bond between the two pulses. By turning it on again at a specific moment, they could then re-link the pulses with a different time interval. As per co-author Prof. Dr. Alfred Leitenstorfer from the University of Constance, "based on our new findings, we can look forward to the realization of versatile technological applications." 

As femtosecond pulses aren't fully understood, the study adds knowledge to a field that could have applications in the future of superfast computing. In 2017, for example, the University of Michigan released a paper on the applications of ultrashort light pulses for fast 'lightwave' computers.

The next step, Henrik and his team say, is to develop a system that lets them produce sequences of short laser pulses with unprecedented precision to further study the phenomenon. Though the team hasn't specified any specific practical applications for which their new research could be utilized, they say that, in the long run, it could help the scientific community to develop better, more precise lasers for a vast number of applications.

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