Physicists at the Univ. of Basel have been successful in generating photons — the quantum particles of light — with only one color. This is useful for quantum information science. The scientists have actively stabilized the wavelength of the photons emitted by a semiconductor thereby neutralizing the charge noise in the semiconductor. The results were developed in close collaboration with the Universities of Bochum, Paderborn and Lyon and have been published in the magazine Physical Review X.
Light consists of quantum particles, so-called photons. With a single photon it is possible to transfer quantum information. The information can be encoded in the polarization or in the phase of the photons’ wave packets and can be used in quantum communication and computation. In such applications, a single-photon source, a device that emits photons one by one, is a prerequisite. One of the most promising platforms for single-photon sources is based on semiconductor quantum dots. One major unsolved problem is, however, that the “color” (or wavelength) of the photons emitted by a quantum dot is not locked to a precise value, rather, it wanders around randomly.
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