Photon entanglement, also known as “Spooky Action at a Distance”, is a promising solution to quantum cryptography and quantum computing. The former will construct a cryptosystem that is impossible to break, and the latter will be capable of solving specific problems much more quickly than any classical computer. An ideal entangled-photon source meeting the following criteria is needed for eventually the practical implementation of quantum information processing: on-demand generation[

- Journal of Semiconductors
- Vol. 41, Issue 1, 010401 (2020)
Abstract
However, the photon extraction efficiency is extremely low because of the refractive indices mismatch between the bulk matrixes and vacuum. Moreover, to realize entangled-photon emission, it is necessary to grow highly symmetric QDs with sufficiently small intrinsic fine-structure splitting (FSS), which will lead to excellent entangled-photon emission via the biexciton-exciton radiative cascade[
Recently, Ding et al. reported a high-efficiency, high-brightness entangled-photon source from semiconductor QDs by using a broadband optical antenna to beam photons[
Figure 1.(Color online) The dielectric antenna consisting of a QD-containing membrane, PMMA spacer, and the GaP solid immersion lens. Reproduced with permission from Ref. [
Their design can be used to improve the extraction efficiency of QDs for practical applications in any telecommunication network. The broadband antenna is also applicable to different optical-active materials. The efficient generation of entangled photon pairs in this report paves the way for the development of various quantum technologies.
References
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