Generation and use of highly entangled photons from semiconductor quantum dots

Tuesday 23rd May 2023, 14:00-15:00

LR7, Information Engineering Building, Oxford

Entanglement is one of the most peculiar phenomena in quantum science and a key resource for quantum technologies. More than two decades after the initial proposal [1], semiconductor quantum dots (QDs) are now beginning to outperform other light sources for the generation of entangled photon pairs. Among different material systems, QDs in the (Al)GaAs material platform have demonstrated the highest degree of polarization entanglement to date together with other appealing features for quantum science and technology [2]. In this talk, we will discuss the properties of GaAs QDs obtained by the droplet etching method and present recent results relevant to their application in quantum communication, i.e. entanglement-based quantum key distribution [3,4], as well as open challenges [5,6].

References

[1]         O. Benson, C. Santori, M. Pelton and Y. Yamamoto, Regulated and Entangled Photons from a Single Quantum Dot, Phys. Rev. Lett. 84, 2513–2516 (2000). http://dx.doi.org/10.1103/PhysRevLett.84.2513

[2]         S. F. C. da Silva, G. Undeutsch, B. Lehner, S. Manna, T. M. Krieger, M. Reindl, C. Schimpf, R. Trotta and A. Rastelli, GaAs quantum dots grown by droplet etching epitaxy as quantum light sources, Appl. Phys. Lett. 119, 120502 (2021). http://dx.doi.org/10.1063/5.0057070

[3]         C. Schimpf, S. Manna, S. F. Covre da Silva, M. Aigner and A. Rastelli, Entanglement-based quantum key distribution with a blinking-free quantum dot operated at a temperature up to 20 K, Adv. Photonics 3, (2021). http://dx.doi.org/10.1117/1.AP.3.6.065001

[4]         C. Schimpf, M. Reindl, D. Huber, B. Lehner, S. F. Covre Da Silva, S. Manna, M. Vyvlecka, P. Walther and A. Rastelli, Quantum cryptography with highly entangled photons from semiconductor quantum dots, Sci. Adv. 7, eabe8905 (2021). http://dx.doi.org/10.1126/sciadv.abe8905

[5]         T. Seidelmann, C. Schimpf, T. K. Bracht, M. Cosacchi, A. Vagov, A. Rastelli, D. E. Reiter and V. M. Axt, Two-Photon Excitation Sets Limit to Entangled Photon Pair Generation from Quantum Emitters, Phys. Rev. Lett. 129, 193604 (2022). http://dx.doi.org/10.1103/PhysRevLett.129.193604

[6]         B. U. Lehner, T. Seidelmann, G. Undeutsch, C. Schimpf, S. Manna, M. Gawełczyk, S. F. Covre da Silva, X. Yuan, S. Stroj, D. E. Reiter, V. M. Axt and A. Rastelli, Beyond the Four-Level Model: Dark and Hot States in Quantum Dots Degrade Photonic Entanglement, Nano Lett. 23, 1409–1415 (2023). http://dx.doi.org/10.1021/acs.nanolett.2c04734