A novel solution has been identified that will make the production of special class of photons faster and easier In the age of high-speed computing, the photon is king.
Thanks to the work by a team of engineers led by Professor Amr Helmy of The Edward S. Rogers Sr. Department of Electrical & Computer Engineering, a novel solution has been identified that will make the production of special class of photons faster and easier.
To enable these technologies to work, a photon – the smallest unit of energy – has to be tightly coupled with another photon.
Ultimately, the entire production of the photons could be completed using a single chip.
With the help of a semiconductor quantum dot, physicists at the University of Basel have developed a new type of light source that emits single photons. For the first time, the researchers have managed to create a stream of identical photons.
They have reported their findings in the scientific journal Nature Communications together with colleagues from the University of Bochum.
A single-photon source never emits two or more photons at the same time. Single photons are important in the field of quantum information technology where, for example, they are used in quantum computers. Alongside the brightness and robustness of the light source, the indistinguishability of the photons is especially crucial. In particular, this means that all photons must be the same color. Creating such a source of identical single photons has proven very difficult in the past.
However, quantum dots made of semiconductor materials are offering new hope. A quantum dot is a collection of a few hundred thousand atoms that can form itself into a semiconductor under certain conditions. Single electrons can be captured in these quantum dots and locked into a very small area. An individual photon is emitted when an engineered quantum state collapses.
Noise in the semiconductor
A team of scientists led by Dr. Andreas Kuhlmann and Prof. Richard J. Warburton from the University of Basel have already shown in past publications that the indistinguishability of the photons is reduced by the fluctuating nuclear spin of the quantum dot atoms. For the first time ever, the scientists have managed to control the nuclear spin to such an extent that even photons sent out at very large intervals are the same color.
Quantum cryptography and quantum communication are two potential areas of application for single-photon sources. These technologies could make it possible to perform calculations that are far beyond the capabilities of today’s computers.
A team of physicists at the University of Toronto (U of T) have taken a step toward making the essential building block of quantum computers out of pure light.
Their advance, described in a paper published this week in Nature Physics, has to do with a specific part of computer circuitry known as a “logic gate.”
Logic gates perform operations on input data to create new outputs. In classical computers, logic gates take the form of diodes or transistors. But quantum computer components are made from individual atoms and subatomic particles. Information processing happens when the particles interact with one another according to the strange laws of quantum physics.
Light particles – known as “photons” – have many advantages in quantum computing, but it is notoriously difficult to get them to interact with one another in useful ways. This experiment demonstrates how to create such interactions.