Quantum computing has been a hot topic for many years. Following this new trend, most of the engineers are trying to reduce the size with smaller parts. LED is used by many scientists to create the necessary changes of the photon particles to make them useful for teleportation, encryption and of course for quantum computing. These LEDs are not as good as the Lasers in many ways, but the scientists hope that their ability to shrink down the particles may make a significant change in the quantum computing.
Parametric down conversion
The method that generates entangled pairs of photon is known as the parametric down conversion and is widely used by the researchers nowadays. In case of Laser, the light is sent through a crystal and the job of the crystal is to divide the ray of light into several different photon particles. In case of a single photon, the crystal divides it into two parts; which have similar properties. So far this is the most recognized method, however it has some limitations.
First of all, the light rays from Laser are divided into multiple or no pairs of photons if they are run through the crystal. So the result might give us too many photons to detect or nothing at all. And most of the time, this is a very costly project, which is not suitable for business purpose.
Using Quantum dots
If we use stimulated quantum dots in the place of Laser and crystal combination, this might give us better result. It was already known to the scientist that a quantum dot can be charged up and it can also be delivered as a single photon particle at once. Recently the technology has developed a little and now it is possible to create a pair instead of only one photon.
How photon gets the energy
The condition that creates multiple quantum dots is known as “biexciton state”. The exciton is a quasiparticle that consists of both an electron and a hole (absence of electron). The biexciton identifies having two sets of electrons and holes. In exciton decay, the electron takes over the hole and the extra energy is transformed into the energy of a photon.
Recently, it was possible to embed a layer of quantum dots into the LED. It was placed in the active region. It was circled by cavity to reduce destruction of the photon. For that they used both alternative current (AC) and direct current (DC) supply.
The DC can produce 71 percent entangled of the current state for the photon pairs which is good, but not good enough when compared to 89 percent of parametric down conversion of Lasers. The AC is accurate by 78 percent entangled. With some modification in the system, it can reach up to 83 percent. Each of these percentages is lower than a crystal-laser combination. With the number of photon pairs, it can be developed and the researchers are trying to do that. They are using the reduced background light emission to make the photon generation livelier. This way, they will respond more and give a better response with electric impulses.