A SCIENTIST working in Cork has developed what must rank as the smallest torch in the world. Measuring 10,000 times smaller than the width of a human hair, it produces individual photons, the smallest particle of light possible.
Made of the same kind of stuff used in silicon microchips, these tiny “quantum dots” have the potential to deliver ultra-secure communications systems and computers that handle information using light rather than electricity.
News of this new work by Dr Emanuele Pelucchi was revealed yesterday on the opening day of the Photonics Ireland 2009 Conference in Kinsale, Co Cork. Dr Pelucchi leads advanced semiconductor materials research at UCC’s Tyndall National Institute.
“These tiny semiconductor particles are so small that they almost act like individual atoms,” according to the head of photonics at Tyndall and chair of the conference, Prof David Cotter. “The ones he is making are the world’s best.”
They are made for one purpose, to produce individual photons of light. Semiconductors can be made to emit light by passing electricity through them, with colourful Leds used in long-life Christmas lighting a familiar example of this.
These Leds might use about a square millimetre of silicon but Dr Pelucchi’s quantum dots are thousands of times smaller. They also produce very consistent light and readily give it up at just one photon at a time.
“Because the quality of the material is so good when you look at the light, the quality of the colour is much better than anyone else has made,” Prof Cotter said.
The quantum in quantum dot means that the devices are so small that they behave according to the bizarre laws of quantum mechanics.
Scientists are trying to exploit these strange characteristics, what Albert Einstein called “spooky action at a distance”, in quantum computers. These use photons of light to do calculations far beyond the limits of today’s most powerful computers.
Researchers are also trying to use quantum effects to develop ultra-secure data transfer using quantum communications. Data encoded using quantum techniques would remain safe from the most determined hacker no matter how good their equipment – unless of course they were using a quantum computer.
These devices are at their earliest stages however, and are still extremely primitive.
The availability of these stable and consistent light-emitting quantum dots would help these technologies to develop further, Prof Cotter said. The biennial conference has brought together more than 250 photonics researchers from across Ireland North and South.
