Entangled multiqubit states are an essential resource for quantum information and computation. Solid-state emitters can mediate interactions between subsequently emitted photons via their spin, thus offering a route towards generating entangled multiphoton states. However, existing schemes typically rely on the excitation-relaxation of the emitter, resulting in single photons limited by the emitter's radiative lifetime, suffering from considerable practical limitations, for self-assembled quantum dots most notably the limited spin coherence time due to Overhauser magnetic field fluctuations. We here propose an alternative approach based on a spin-$\mathrm{\Lambda }$ system that overcomes the limitations of previous proposals. Studying the example of spin-flip Raman scattering of self-assembled quantum dots in Voigt geometry, we argue that weakly driven hole spins constitute a promising platform for the practical generation of frequency-entangled photonic cluster states.

• Received 17 February 2018

DOI:https://doi.org/10.1103/PhysRevA.98.022318