Nobel Prize in Physics to …

The 2018 Nobel Prize for Physics was awarded half to Arthur Ashkin and the other half to Gerard Mourou and Donna Strickland for the fundamental research and innovations in the field of laser optics.

Their work has allowed the development of advanced precision instruments for handling extremely small objects, and very high-intensity laser pulses to be used, for example, in surgical operations. Arthur Ashkin is affiliated with the Bell Laboratories of Holmdel, USA; Mourou works at the Eole Polytechnique of Palaiseau, in France and at the University of Michigan, USA; Donna Strickland is active at the University of Waterloo, Canada.

Ashkin invented optical clasps able to grasp and move viruses, bacteria and living cells without damaging them, creating new opportunities to study invisible particles at the base of life. Mourou and Strickland have developed a technique called chirped pulse amplification (CPA) based on shorter, compressed and intense laser pulses ever created, and which is today the basis for high-intensity laser devices used in medicine and in industry.

Donna Strickland is the third woman awarded with the Nobel Prize in Physics throughout the history of the award. Before her there were only Marie Curie, in 1903, and Maria Goeppert-Mayer, in 1963. The scientist, reached by telephone from the Nobel committee, she seemed moved and honored for the assignment, but also amazed by such a small number of award-winning women.

BUILDINGS TO MOVE. Arthur Ashkin, inspired by the beam of Star Trek and the invention of the first laser, in 1960, realized that a laser would be a perfect tool to try to move tiny particles without touching them. First he realized that transparent micro spheres are put into motion when illuminated by laser beams, and that pushing them is the pressure of the beam itself. Unexpected, it is the gradient of this pressure, which is more intense in the center and decreases at the ends of the ray: the particles are then pushed into the center of the light beam.

If the laser beam is pointed upwards, the particles levitate, because the radiating pressure contrasts the gravity. By adding a lens to focus the laser light, the particles are guided to the point with the highest light intensity. In this way, light traps are created: in other words, optical pincers that can be used to study, push or cut proteins, molecular motors, DNA and other tiny bricks of biological processes.


The technique of Mourou and Strickland, the CPA, consists instead of taking a laser beam, dilating it in time, amplifying it and then compressing it again so that it incorporates more light into a small portion of space, and that the intensity of that pulse grows exponentially.

The ultra-precise lasers created in this way make it possible to cut or drill holes even in living tissues. Millions of eye operations are performed every year thanks to this technique.

The CPA can also be used to make surgical stents that strengthen or enlarge the blood vessels, to improve data storage systems or to implement extremely fast image capture systems. The innumerable areas of applications of both discoveries have not yet been fully explored. But, in the spirit of Alfred Nobel, it is about research for the benefit of humanity.





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