Stockholm: Three scientists who created the technology behind digital photography and helped link the world through fibre-optic networks shared the 2009 Nobel Prize in physics on Tuesday.

Digitizing light: The winners of the Nobel Prize in physics (from left) Charles Kao, Willard S. Boyle and George Smith. Reuters / Scanpix

Charles K. Kao was cited for his breakthrough involving the transmission of light in fibre optics while Willard S. Boyle and George E. Smith were honoured for inventing an imaging semiconductor circuit known as the CCD sensor.

The Royal Swedish Academy of Sciences said all three have US citizenship. Kao also holds British citizenship while Boyle is also Canadian.

The award’s 10 million kronor (Rs6.8 crore) purse will be split between the three, with Kao taking half and Boyle and Smith each getting one-fourth. The three also receive a diploma and an invitation to the prize ceremonies in Stockholm on 10 December.

Kao, who was born in Shanghai and is a British citizen, was cited for his 1966 discovery that showed how to transmit light over long distances through fibre-optic cables, which became the backbone of modern communication networks that carry phone calls and high-speed Internet data around the world.

“With a fibre of purest glass, it would be possible to transmit light signals over 100km, compared with only 20m for the fibres available in the 1960s," the citation said.

Boyle and Smith worked together to invent the charged-coupled device (CCD), the eye of the digital camera found in everything from the cheapest point-and-shoot to high-speed, delicate surgical instruments.

The citation said that Boyle and Smith “invented the first successful imaging technology using a digital sensor, a CCD". It said that technology builds on Albert Einstein’s discovery of the photoelectric effect, for which he was awarded the Nobel physics prize in 1921. The two men, working at Bell Laboratories in New Jersey, designed an image sensor that could transform light into a large number of image points, or pixels, in a short time. “It revolutionized photography, as light could now be captured electronically instead of on film," the Academy said.

The physics award is the second of the 2009 Nobel Prizes to be announced. On Monday, three American scientists shared the Nobel Prize in medicine for discovering a key mechanism in the genetic operations of cells, an insight that has inspired new lines of research into cancer.