A Budapest boyhood
Dennis Gabor was born Günszberg Dénes in Budapest on June 5, 1900, the eldest son of a Jewish family. His father, Bertalan Gabor, was the director of a mining company; his mother was Adrienne. In 1902 the family changed its surname from Günszberg to Gábor, a common step among assimilating Hungarian Jews of the time, and the family later converted to Lutheranism.
His love of physics arrived suddenly, he recalled, at the age of fifteen. He taught himself calculus and worked through the largest physics textbook of the day, and with his younger brother George he set up a small laboratory at home where they repeated the newest experiments of the era, with X-rays, radioactivity and wireless. He was especially fascinated by Ernst Abbe’s theory of the microscope and by Gabriel Lippmann’s method of colour photography, ideas that would return in his greatest work thirty years later. During the First World War he served in the Hungarian artillery in northern Italy.
An engineer in Berlin
When it came time for university, Gabor chose engineering rather than physics. Hungary had only a handful of physics professorships, and, as he later put it, who could be presumptuous enough to aspire to one of them? He began at the Budapest Technical University in 1918 and moved to the Technische Hochschule in Berlin-Charlottenburg, earning his diploma in 1924 and his doctorate in 1927. He sneaked away as often as he could to the University of Berlin, where Einstein, Planck, Nernst and von Laue were lecturing.
For his doctorate he built one of the first high-speed cathode ray oscillographs, and in the process made the first iron-shrouded magnetic lens for electrons, a forerunner of the lenses in electron microscopes. In 1927 he joined the electrical company Siemens & Halske, where he invented a high-pressure quartz mercury lamp with a molybdenum tape seal that went into millions of street lamps. He called it his first lesson in serendipity, because he had been trying to make a cadmium lamp.
Refugee in Rugby
When Hitler came to power in 1933, Gabor, considered Jewish under Nazi racial thinking despite his family’s conversion, left Germany. After a short time in Hungary he went to England in 1934, in the depths of the Depression, when jobs for foreigners were scarce. He found work at the British Thomson-Houston company in Rugby on an inventor’s agreement, and stayed in its research laboratory until the end of 1948.
The years after the Second World War were his most fruitful. He wrote pioneering papers on communication theory, whose mathematical tools, now called Gabor functions and Gabor filters, are still used in signal processing and image analysis. He developed a system of stereoscopic cinema. And he made the invention that would define his life.
Writing down the whole picture
Gabor was trying to improve the electron microscope. By the 1940s it could magnify a hundred times better than the best light microscope, yet it still could not resolve individual atoms, because electron lenses were hopelessly imperfect; he compared the best of them to a raindrop rather than a fine glass lens. After pondering the problem for a long time, he wrote, a solution suddenly dawned on him one fine day at Easter 1947: why not take a bad electron picture, but one that contains the whole information, and then correct it by optical means?
An ordinary photograph records only the brightness of light. Gabor’s idea was to record the light waves themselves, their brightness and their phase, by letting the light scattered from an object interfere with a clean reference wave. The result is a pattern of fine fringes that looks nothing like the object. But shine a similar wave back through the pattern, and the original light waves are rebuilt, creating a full three-dimensional image. He called the recorded pattern a hologram, from the Greek holos, whole, because it contained the whole information. He filed a patent in December 1947 and in 1948, with his assistant Ivor Williams, carried out the first experiments, using the filtered light of a mercury lamp.
Waiting for the laser
The early results were tiny and blurred. Holography needs coherent light, waves marching perfectly in step, and no such light source existed. Gabor’s electron-microscope project, carried out from 1950 to 1953 with the AEI laboratory at Aldermaston, produced respectable results but fell short of its goal; he said they had started twenty years too early. Around 1955 holography went into what he called a long hibernation.
It woke explosively after the invention of the laser in 1960. In 1962 Yuri Denisyuk in the Soviet Union and Emmett Leith and Juris Upatnieks at the University of Michigan made the first laser holograms of three-dimensional objects, far better than anything Gabor had managed. Within a few years thousands of laboratories were making holograms, and the field Gabor had founded became a world success.
Holography in everyday life
Most people carry Gabor’s invention in their wallets. Security holograms are very hard to forge because they are copied from a master hologram that requires specialised equipment to make, and they appear on banknotes in many countries, including the euro area, the United Kingdom, Canada and Japan, as well as on credit and bank cards, passports and identity cards.
In engineering, holographic interferometry, in which two holograms of an object are recorded before and after it is stressed, reveals movements smaller than a wavelength of light. Gabor himself described it in his Nobel lecture. It is widely used to measure strain and vibration in structures and to visualise the flow of air and fluids, and pulsed laser holography can freeze events lasting billionths of a second. Researchers have also used holograms to store data throughout the volume of a material and to image the eye. The ideas behind Gabor’s communication theory, meanwhile, live on in sound synthesis and computer vision.
Imperial College and the future of society
On January 1, 1949, Gabor joined Imperial College London, first as a reader in electronics and from 1958 as professor of applied electron physics, until he retired in 1967. With his doctoral students he tackled many difficult problems, building a holographic microscope, a flat, thin colour television tube and an early learning machine that could predict and recognise patterns in time series. He was elected a Fellow of the Royal Society in 1956, received the IEEE Medal of Honor and was made a CBE in 1970, and in 1971 he received the Nobel Prize in Physics for his invention and development of the holographic method.
From 1958 onward he devoted more and more of his time to the future of industrial civilisation. He believed that technology had outrun society’s institutions and that inventive minds should treat social inventions as their first priority. He set out his views in Inventing the Future (1963), Innovations (1970) and The Mature Society (1972), and he led a working group for the Club of Rome whose 1978 report, Beyond the Age of Waste, was an early warning about the waste of resources and energy.
Identity and private life
Gabor was born into a Jewish family in Budapest, one of many in the city’s prosperous and largely assimilated Jewish middle class. His family changed its name and converted to Lutheranism, and as an adult he described himself as a benevolent agnostic. None of that protected him in Germany, where the Nazis classed him as Jewish, and his flight in 1933 made him one of the many refugee scientists who enriched British science. He is listed among Jewish Nobel laureates by the Jewish Virtual Library.
In 1936 he married Marjorie Louise Butler, the daughter of a Rugby family; they had no children. After retiring from Imperial College he worked as a staff scientist at CBS Laboratories in Stamford, Connecticut, with his lifelong friend Peter Goldmark, and he spent much of his later life in Lavinio, Italy. He was honoured in Hungary as well as Britain, becoming an honorary member of the Hungarian Academy of Sciences in 1964.
Legacy
Dennis Gabor died in a nursing home in London on February 9, 1979, at the age of 78. His legacy is visible in a way that few physicists’ work is. Holography, the method he invented while trying to see atoms, protects money and identity documents across the world, helps engineers find weaknesses in structures, and has become a basic tool of optics. His own motto for the future of society, that futures can be invented, describes his career as well as any: a refugee engineer who kept turning setbacks into new ideas.
Sources & further reading
Dennis Gabor, Biographical, NobelPrize.org · Dennis Gabor, Holography, 1948–1971, Nobel Lecture (PDF), NobelPrize.org · Dennis Gabor, Wikipedia · Holography, Wikipedia · Dennis Gabor, Jewish Virtual Library · Dennis Gabor, Wikiquote · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.