If two different colored lasers are used to excite a quantum system, it can be excited via a swing up process. The quantum system has a spiral movement. Credit: University of Mnster.
The "second quantum revolution" is currently in full swing after the first quantum revolution. New technologies based on quantum physics are being developed by experts from all over the world. Information is written and sent in light. The light needs to be in a single photon state for quantum effects to work. What is the best way to generate a single photon state? In the PRX Quantum journal, researchers from Mnster, Bayreuth and Berlin have proposed a new way of preparing quantum systems in order to develop components for quantum technology.
The experts think that using quantum systems for generating single photon states is very promising. A quantum dot is an example of a quantum system. This is a small structure of transistors. The lasers can be used to control quantum dots. Although quantum dots have similar properties to atoms, they are embedded in a crystal matrix which is more practical for applications. Dr. Heindel says that quantum dots are excellent for generating single photons, and that is something they are already doing in their labs. He says there is still room for improvement in transferring technology from the lab to real applications.
One challenge that has to be overcome is to separate the generated single photons from the exciting laser pulse. The researchers propose a new method of solving the problem. The lead author of the study explains that the quantum system has a swing-up process. We use one or more lasers which have different frequencies than the ones in the system. This makes it very easy to find the source of the spectrum.
In quantum communication, a photon is generated in a quantum system and transmitted via an optical cable to a detector system. Credit is given to the Physikalisch-Technische Bundesanstalt and the University of Berlin.
The "swing-up process" is the behavior of the particles excited by the laser light in the quantum system. Two lasers are used to emit light. The interaction of the pulse with one another causes a rapid change in the state of the particle, as it dips towards the ground state again. It does not fall back to its previous level, but is excited more with each swing up until it reaches the maximum state. The advantage of this method is that the laser light doesn't have the same frequencies as the excited particles. The quantum dot can be clearly assigned.
Guidelines for experimental implementation were provided by the team after they simulationulated this process in the quantum system. "We explain the physics of the swing-up process, which helps us to understand the dynamics in the quantum system," says Dr.
They need certain properties to be able to use the photons in quantum communication. Any preparation of the quantum system should not be affected by disruptive influences. The interaction with the surrounding material is a big problem in quantum dots. Prof. Martin Axt, who heads the team of researchers from Bayreuth, says that the simulations show that the properties of the photons generated after the swing-up process are comparable with the results of established methods.
The study is considered theoretical work. The proposal is very close to realistic experimental laboratory conditions, and the authors are confident that an experimental implementation of the scheme will soon be possible. The researchers are taking a further step towards developing quantum technologies of the future.
More information about Swing-Up of Quantum Emitter Population Using Depulses, PRX Quantum is available. There is a book titled "PRXQuantum.2.040354."
A new way of preparing quantum systems to develop components for quantum technology was retrieved on December 21, 2021.
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