The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics 2018 “for groundbreaking inventions in the field of laser physics” with one half to Arthur Ashkin “for the optical tweezers and their application to biological systems” and the other half jointly to Gérard Mourou and Donna Strickland “for their method of generating high-intensity, ultra-short optical pulses”.

Optical tweezers

Arthur Ashkin invented optical tweezers that grab particles, atoms, viruses and other living cells with their laser beam fingers. This new tool allowed him to – using the radiation pressure of light – to move physical objects. He succeeded in getting laser light to push small particles towards the centre of the beam and to hold them there. A major breakthrough came in 1987, when Ashkin used the tweezers to capture living bacteria without harming them. He began studying biological systems and optical tweezers are now widely used to investigate the machinery of life.

Chirped pulse amplification

Gérard Mourou and Donna Strickland paved the way towards the shortest and most intense laser pulses ever created by mankind. Their revolutionary article was published in 1985. They succeeded in creating ultrashort high-intensity laser pulses without destroying the amplifying material. First they stretched the laser pulses in time to reduce their peak power, then amplified them, and finally compressed them. If a pulse is compressed in time and becomes shorter, then more light is packed together in the same tiny space – the intensity of the pulse increases dramatically. Strickland and Mourou’s newly invented technique, called chirped pulse amplification, CPA, soon became standard for subsequent high-intensity lasers. Its uses include the millions of corrective eye surgeries that are conducted every year using the sharpest of laser beams.

About the Laureates in Physics

Arthur Ashkin, born 1922 in New York, USA. Ph.D. 1952 from Cornell University, Ithaca, USA.

Gérard Mourou, born 1944 in Albertville, France. Ph.D. 1973.

Donna Strickland, born 1959 in Guelph, Canada. Ph.D. 1989 from University of Rochester, USA.

Illustration of Arthur Ashkin, Gérard Mourou and Donna Strickland: Niklas Elmehed. © Nobel Media

Read also:

The Nobel Prize in Physiology or Medicine 2018

The Nobel Prize in Chemistry 2018