If you’re reading this online, and if you have just been surveying portraits of the new Nobel Laureates, then it’s safe to say that you’re benefitting directly from the two achievements rewarded with the 2009 Nobel Prize in Physics. The optical fibers along which this Speed read is travelling, and the digital imaging which underlies practically all modern photography, are the direct consequences of that work, done 40 years ago.
Optical fiber communication is now ubiquitous, but when Charles Kao first suggested that glass fibers could be used for long range information transfer, his ideas were met with scepticism. It had long been understood that glass fibers could act as waveguides for light, allowing, for instance, the development of short range optical fibers for probing the inner recesses of our bodies. But such fibers were thought to be far too inefficient for any long range use, light transmission falling to negligible levels after just a few meters. In a 1966 paper, Kao and his colleague George Hockham put forward the radical suggestion that impurities in the glass were responsible for this inefficiency, and that truly pure glass would give vastly improved light transmission. When, four years later, optical fibers of pure glass were at last fabricated, Kao and Hockham’s prediction was found to be correct, paving the way for the development of today’s ubiquitous, efficient, energy-saving optical cable networks.
Digital image capture, now so much a part of everyday life, got its start from an afternoon’s brainstorming between Willard Boyle and George Smith, colleagues at the famous Bell Laboratories. Working in the semiconductor division, in 1969 they were asked by their boss to come up with a novel technology for information storage. The device they sketched on the board that afternoon was an image sensor based on Albert Einstein’s photoelectric effect, in which arrays of photocells would emit electrons in amounts proportional to the intensity of incoming light. The electron content of each photocell could then be read out, transforming an optical image into a digital one. Their charge-coupled device (CCD), as they named it, proved not to have a future in memory storage, but rather gave rise to an explosion in digital imaging, with the first CCD-based video cameras appearing in the early 1970s. Although CCDs are to some extent now supplemented by competing technologies, their use in applications ranging from digital cameras to the Hubble space telescope has completely transformed image processing.