Nobel Prize in Physics (2018)

The coveted Nobel Prize in Physics (2018)- an award worth a staggering 9 Million Swedish Kronor (7.4 Crores of Indian ₹) - was announced today by the Royal Swedish Academy for Sciences and has been awarded to three distinguished scientists Dr. Arthur Ashkin, Bell Laboratories, Holmdel, USA, Dr. Gérard Mourou, École Polytechnique, Palaiseau, France, University of Michigan, Ann Arbor, USA and to Dr. Donna Strickland, University of Waterloo, Canada, “for their groundbreaking inventions in the field of laser physics”. Ashkin has been awarded half the prize “for the optical tweezers and their application to biological systems”, while the other half is shared by Mourou and Strickland for “their method of generating high-intensity, ultra-short optical pulses”.

The immense fecundity that the field of “Laser Physics” carries can be visualised in the best spirit of Alfred Nobel – for the greatest benefit to humankind.

Two of the three awardees - Arthur Ashkin and Donna Strickland - have created a sort of an unprecedented record. Ashkin ( born September 2, 1922) aged 96 years, is the oldest living person to have received this honour. When the Royal Swedish Academy broke this news to him and requested him for a live telephonic interview with the press, the actively young scientist - in his later part of the 90s - excused himself by stating that he was engrossed in his new scientific paper and don’t have time to spare for the live interview. So much for the love of science. Donna Strickland is only the third woman winner of the Physics Nobel award, along with Marie Curie, who won in 1903, and Maria Goeppoert-Mayer, who was awarded the prize in 1963.

Arthur Ashkin invented optical tweezers that grab particles, atoms, viruses and other living cells with their laser beam fingers. 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 immediately began studying biological systems. Optical tweezers are now widely used to investigate the machinery of life.

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 and was the foundation of Strickland’s doctoral thesis. Using an ingenious approach, 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.

The inventions being honoured this year have revolutionised laser physics resulting in shedding new light into extremely small objects and incredibly fast processes that can now be studied in a new light. This will not only help physics, but also other sciences - chemistry, biology and medicine - which will be benefitted from the resulting precision instruments that can be used in basic research and practical applications.

No other scientific discovery of the 20th century has been demonstrated with so many exciting applications as laser (Light Amplification by Stimulated Emission of Radiation). The basic concepts of laser were first given by an American scientist, Charles Hard Townes and two Soviet scientists, Alexander Mikhailovich Prokhorov and Nikolai Gennediyevich Basov who shared the coveted Nobel Prize (1964). T H Maiman of the Hughes Research Laboratory, California, was the first scientist who experimentally demonstrated laser by flashing light through a ruby crystal, in 1960. Ever since new applications of lasers have been announced in various fields almost regularly. Laser finds applications In the fields of communication, Industry, medicine, military operations, scientific research, etc. Besides, laser has already brought great benefits in surgery, photography, holography, engineering and data storage.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors, which helped in the discovery of the first gravitational waves produced by two giant merging blackholes last year leading to a Nobel Prize in Physics in 2017, also owes its genesis to Lasers. Incidentally a new gravitational wave detector to measure ripples in the fabric of space and time is set to be built in India by 2025, in collaboration with universities from across the globe, thus helping Indian scientists.

Laser is a powerful source of light having extraordinary properties, which are not found in the normal light sources. The unique property of laser is that its light waves travel very long distances with very little divergence. Laser light is created through a chain reaction in which the particles of light, photons, generate even more photons. These can be emitted in pulses. Ever since lasers were invented, almost 60 years ago, researchers have endeavoured to create more intense pulses.

Many applications for the new laser techniques are waiting just around the corner – faster electronics, more effective solar cells, better catalysts, more powerful accelerators, new sources of energy, or designer pharmaceuticals. There is already speculation about the next step: a tenfold increase in power, to 100 peta watts and may be extending it further to the power of a zettawatt (one million petawatts, 10 to the power 21 watt), or pulses down to zeptoseconds, which are equivalent to the almost inconceivably tiny time of 10 to the power -21 seconds. New horizons are opening up, from studies of quantum physics in a vacuum to the production of intense proton beams that can be used to eradicate cancer cells in the body.

Along with the development in the research in laser technology and modern optics theory and their application, optics has been completely endowed with new contents and is playing an important role in scientific and technological progress. In recent years, the discipline has put great emphasis on updating the contents and collaborative research programs interdisciplinaryly.