Angular momentum transfer from photon polarization to an electron spin in a gate-defined quantum dot

Fujita, T. and Morimoto, K. and Kiyama, H. and Allison, G. and Larsson, M. and Ludwig, Ar. and Valentin, S.R. and Wieck, A.D. and Oiwa, A. and Tarucha, S.

Volume: 10 Pages:
DOI: 10.1038/s41467-019-10939-x
Published: 2019

Gate-defined quantum dots (QDs) are such a highly-tunable quantum system in which single spins can be electrically coupled, manipulated, and measured. However, the spins in gate-defined QDs are lacking its interface to free-space photons. Here, we verify that a circularly-polarized single photon can excite a single electron spin via the transfer of angular momentum, measured using Pauli spin blockade (PSB) in a double QD. We monitor the inter-dot charge tunneling which only occur when the photo-electron spin in one QD is anti-parallel to the electron spin in the other. This allows us to detect single photo-electrons in the spin-up/down basis using PSB. The photon polarization dependence of the excited spin state was finally confirmed for the heavy-hole exciton excitation. The angular momentum transfer observed here is a fundamental step providing a route to instant injection of spins, distributing single spin information, and possibly towards extending quantum communication. © 2019, The Author(s).

« back