The Victorian inventions running on brass and steam with their spiraling cogs and thrusting pistons, their whirling regulators and bells and whistles, could have led us to such a different world of computing had Charles Babbage moved faster and made a Difference. Then, the twitching electrical relays, the glowing thermionic valves of the twentieth century, with less steam more haste, gave us room-sized computers and won the Second World War for The Allies. Silicon led us into the valley of kings with the development of the integrated circuit and so today there is far and away more computing power in each of our pockets than was needed to take us to the Moon.
But, it's time to slough off the electrons and shed a little light. For it is photons that will twinkle in the high-speed computers of the almost near future, no more the dawdling of electrons and their sluggardly ways. We might soon be computing at c. c is for "celeritas" the Latin word for speed that so famously appears in that century-old theory that gives us GPS navigation and twins that age at different rates when one of the pair heads for the stars - Einstein's theory of relativity.
However, it's the photon itself, the particle of light mused on by philosophers for centuries but made manifest only in quantum theory, that great bugbear of Albert's, will change everything, quantum computing notwithstanding. We already use light in data storage to write and read optical disks, and, of course have done for quite some time from the laser disk and CD to the Blu-Ray player and beyond. Many a TV has an optical connection between its audio output and the input on the speaker system and even this is not a new gimmick, with "optical out" being familiar to HiFi buffs for at least a quarter of a century. Meanwhile, suggestions of Li-Fi that will use the lighting system in your home or office to beat Wi-Fi one hundredfold on download and upload is just around the corner.
It was a paper highlighted this week, as many people put match to candle to light up the solstice gloom in this hemisphere, that caught my eye when scanning the literature and the newsfeeds for winter inspiration for this week's Comment. There is an intriguingly titled paper just about to appear in the journal Physical Review X: "Nanophotonic optical isolator controlled by the internal state of cold atoms."
It sounds a bit esoteric at first glance, but this work by researchers at the Vienna Center for Quantum Science and Technology, in Austria, holds the promise of a diode for photons. As you will no doubt know the electronic diode is a crucial component of countless circuits and in the form of the light emitting diode lies at the heart of modern flat displays that give us tablet PCs, smart phones and more and is also lighting our rooms and street signage with increasing frequency, as it were. However, light-based (photonic) circuits could be faster and consume a lot less power than their electronic counterparts. To build those photonic circuits we will need the photonic analogs of the familiar electronic components, hence the excitement surrounding this latest paper.
The electronic diode is a one-way street for electrons, the photonic diode will apply the same restrictions to light traffic. The prototype from the Austrian team of Clément Sayrin and Juergen Volz controls the passage of individual photons through a fiber through their interaction with cold atoms trapped in the vicinity of the nanometer-thin optical fiber preventing light "flow" in one direction by twenty times greater than the flow in the opposite direction. Moreover, the device can operate on single photons, and so it could itself be developed into a component for a quantum optical network. When such work brings new light to the world of computing we will see soon enough how silicon chips seem as quaint as all that brass and steam of the Victorian age and our computing will all be done at the speed of light.
David Bradley blogs at Sciencebase Science Blog and tweets @sciencebase, he is author of the bestselling science book "Deceived Wisdom".