2009 Nobel Prize in Physics
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NEWS AWARDS ABOUT THE 2009 NOBEL PRIZE IN PHYSICS THE 2009 NOBELPRIZE IN PHYSICS I NOBEL COMMITTEE REWARDS RESEARCH IN TECHNOLOGY /e Nobel Prizes in Physics of 2009 University of California at Berkeley, ged entirely his work. "/is has been have been awarded for two scientific and who joined Bell Labs aWer recei- the most important development in developments that have a profound ving his PhD and started work on the astronomy the last 30 years or so, if impact on both consumer techno- CCD. "My reaction was of absolute not more, for the simple reason that logy and scientific research. Charles delight, I found out that the work we the predecessor of all the electronic K. Kao of the Chinese University in did was actually worth the Nobel detectors was the photographic plate, Hong Kong was awarded the Nobel Prize," says Séquin. and the quantum efficiency of the Prize "for groundbreaking achieve- "I think it is great to give a prize for electronic plate was between 1 and 3 ments concerning the transmission something that is technology, cer- percent. Now, with the solid-state of light in fibres for optical commu- tainly for the science that it enabled," detector, the quantum efficiency nication. /e second half of the prize says Steve Howell, an astronomer at reaches almost 100 percent," says ᭢ Charles was awarded to two researchers from the Planetary Science Institute in Baade. Unlike photographic plates, Kao in his Bell Labs, Willard S. Boyle and Tucson,Arizona. CCDs allow the repeated exposure of laboratory at the Standard George E. Smith "for the invention of For astronomers, the invention of the the same area of the sky, making Telecommu- an imaging semiconductor circuit, CCD was indeed a revolution. For extremely faint objects visible. "/e nications the CCD sensor." Although the Dietrich Baade,the leader of the Opti- ultra-deep field images obtained with Laboratory in the U.K. in importance of the rewarded work is cal Detector Team of the European the Hubble Space Telescope are the the 1960s. evident,it came to many as a surprise. Organisation for Astronomical result of sixty hours of observations– (European Pressphoto It was a surprise to Carlo Séquin,now Research in the SouthernAtmosphere a tremendous number." says Baade. Agency) at the College of Engineering at the (ESO),in Garching,Germany,it chan- Howell still remembers how the ini- tial design of the Hubble Space Telescope incorporated photographic plates that would be parachuted to Earth or picked up by visiting crews. "/e study of distant supernovae, dark energy and dark matter, none of this would have been enabled without CCDs," says Howell. /e commercial impact of optical fibres is even more important than that of CCDs, but the impact on scientific research is definitely as great./e fast transmission of data in fibres not only allows the setting up of super-fast networks like "the grid" developed by CERN for the distribu- tion of data obtained with the LHC, but also of "virtual observatories" in astronomy and other areas of science. 08 EPN 40/6 AWARDS NEWS Direct applications of optical fibres were working on a so-called "bubble the idea. "In this case they didn't do also abound, in photonics, laser memory" for computers, and not on that." he says.And he also comments research, and even in telescopes. an imaging device."If you are interes- on the fact that the 1966 paper by Baade explains how the spectrograph ted in the basic concept of the charge Kao [1], cited by the Nobel Commit- used in the search of exoplanets with transport, then I think it is absolutely tee, in which he outlines how optical HARPS (High Accuracy Radial Velo- reasonable to pick Boyle and Smith fibres can transport signals over long city Planet Searcher) is connected via because they had this crucial discus- distances, also has a co-author, optical fibres to ESO's 3.6-metre teles- sion in their office that lead to this George Hockham, who doesn’t share cope at the La Silla Paranal idea," says Séquin. "But if you read the Nobel Prize. Observatory in Chile. /e individual the report of the Nobel Committee,it It is clear that the researchers who feel fibres collect the light of a large num- is 90 percent about image sensors leW out are the victims of the rule of ber of stars,and carry the light to a and how to make image sensors of limiting the Nobel Prize to maximally spectrograph mounted in a vacuum high resolution," says Séquin. It was three recipients. Increasingly, vessel,making the extremely sensitive a colleague of Séquin at Bell labs, advances in technology and science instrument independent of telescope Michael Tompsett, who in fact built are the result of large teams.“Clearly motions and temperature changes. the first CCD, and who applied for a the development of a honest-to-God Unfortunately, the nomination of patent for the device. It was also viable CCD camera involved in the Boyle and Smith for the development Tompsett who devised the techno- order of 200 individuals,”comments of the CCD became the subject of a logy for reading out the information Séquin. Perhaps the Nobel Commit- controversy. During the days follo- stored on the CCD. "/is principle tee should relax its limitation on the wing the announcement of the Nobel was clearly invented by Tompsett," number of nominees. I laureates early October, several says Séquin. researchers questioned on a blog of According to Govind Agrawal, who III A. Hellemans IEEE Spectrum whether the duo leads the Nonlinear Fiber Optics really could be viewed as the inven- Group at the University of Rochester References tors of the CCD. "/e comments in Rochester, New York, the Nobel were flying back and forth,there is no Committee generally divided the [1] K.C. Kao and G.A. Hockham, Dielectric- Fibre Surface Waveguides for doubt that there is a controversy," prize between the team who got the optical frequencies, Proc. IEEE 113, says Séquin. In fact Boyle and Smith idea and the team who implemented 1151 (1966). THE 2009 NOBELPRIZE IN PHYSICS II CHARLES KAO, PIONEER IN OPTICAL FIBRES /e world is pending on a tiny and the coaxial cable CATV lines and Cables (STC) in Harlow,UK,and thread, a thread of glass. Optical connecting the users’ homes. Electri- there he developed his groundbrea- fibre is vastly deployed all over the cal signals get attenuated on the lossy king ideas of how to carry light with world,to carry our telephone conver- copper lines, necessitating lots of extremely low losses through glass sations, computer data, TV signals, amplifiers all over in the networks. fibre. He first presented his results in the internet with its exploding /e bandwidth of these lines is quite January 1966 in London to the Insti- gamma of services, etc. Our econo- limited, and is running out of steam tute of Electrical Engineers (IEE). mic, social and cultural activities in view of the fast growing capacity would come to a standstill without needs of the internet. Moreover, as Low-loss light guiding the huge communication streams the world’s resources are expiring, /e guiding of light in curved media which the tiny silica glass fibre is able copper gets ever more expensive. was already observed much earlier, to carry.When Samuel Morse intro- Charles Kao, who was born in 1933 e.g. by noticing that in illuminated duced the telegraph and Alexander in Shanghai, and got his PhD degree fountains light was guided by the Graham Bell the telephone,the world in Electrical Engineering in the curved water beams. /e light gui- was dependent on copper wires.And Imperial College London in 1965, ding is actually realized by‘total still large parts of the communication recognized these shortcomings internal reflection’: light propagating networks are using copper, in parti- already in the mid 60’s. He worked as in a material with a high refractive cular the twisted-pair telephone lines an engineer in Standard Telephones index is reflected at the interface with III EPN 40/6 09 NEWS AWARDS III a medium with lower refractive index, provided that the incidence angle on this interface is larger than the critical angle. As this reflection is very efficient and causes negligible losses, light can be confined and gui- ded through the water beam. Obviously more stable solutions than water beams are needed, so similar experiments were done with homo- geneous threads of glass. Endoscopy could be done with many of these glass threads united in a single cable. However, small scratches and other ᭡ FIG. 1: Silica optical fibres (diameter 125μm each) irregularities at the surface of the glass destruct the total internal reflec- Glass in the US indeed demonstrated Hence this modal dispersion pheno- tion process, and light leaks out. light guiding in such optical fibre menon limits the rate at which Hence the losses of such homoge- with less than 20 dB/km loss. pulses can be transmitted, so the neous threads were too high for Modern optical fibre has a standar- bandwidth of the fibre. /e modal guiding light over larger distances. dized outer diameter of only 125 dispersion can be reduced by accele- Moreover, impurities in the glass micrometer, within 1 μm. /is is rating the light rays which are itself contributed to the losses. about the thickness of a human hair making the larger excursions when Charles Kao came up with fused (see Fig. 1). Regarding attenuation, it travelling through the core, so by silica (silicon dioxide) as the perfect has made a huge progress since its reducing the refractive index of the material for very low loss light gui- invention, while still following Kao’s core towards the cladding, see Fig.