Ultra-short pulses, an overview

We are entering the Control Age, where the goal is to control chemical processes, control how the electrons orbit the nucleus of the atom, control how materials behave on an atomic level and produce nano-scale “machine parts”. This will give us a yet unseen control over the processes that influence our everyday lives, and will ultimately give us the opportunity to perform extremely precise experiments that can challenge our understanding of the fundamental laws in physics.

Acquiring such an extreme control is possible with lasers emitting ultra-short pulses.

In femtosecond pulsed lasers the laser light is emitted in trains of ultra-short pulses. Femtosecond pulses are very brief: 1 fs is 10-15 s, and the duration of one period of the oscillating electromagnetic field is around 1-2 fs in the visible regime.

 

Today it is possible to generate pulses short enough to reach the time scale of the electron orbiting the nucleus of the atom, as well as the time scales of molecular vibrations and chemical reactions. These impulses can therefore be used to generate snapshots of these atomic, molecular and chemical processes, and ultimately also manipulate them.

 

Pulsed lasers can also be used for extremely precise frequency measurements and to selectively cut in living cells with precision on the nano scale. Finally, they are instrumental in generating the largest peak intensities ever observed, which can be used to understand the relativistic nature of the elementary particles and the properties of black holes.

 

I was recently asked the nerve-wracking question: how is the world influenced in 25 years by ultra-fast lasers and pulses? My best guess is this: In 25 years pulsed lasers will pass from being an exotic industrial tool and a part of a high-tech laboratory to be part of the everyday of most people. We will see laser cutters that can cut in any material, nanosurgery with lasers repairing single cells, handheld laser scanners that quickly can determine the material properties of a sample, big industrial plants producing nanobots cut with nanoscale precision using pulsed lasers, hitherto unthinkable chemical reactions kept in awe with pulsed lasers. We will also see a colossal development in the precision and control that these lasers offer, and that will have a fundamental impact on the understanding of the laws of physics and the structure of the universe.

 

Further information can be found here. This is the draft version of a chapter for an upcoming book "Beyond Optical Horizons" published by DTU Fotonik, where the idea is to try and predict how our research will affect the society in 25 years.

 

In this section you can also read more about how micromachining with femtosecond laser pulses can make material damage with a resolution much less than the wavelength of the laser light, and howcome nanosurgery can cut in a living cell without even breaking the cell membrane. Read more under Micromachining - nanoscale manipulation of materials.