Measurement of spin coherence using Raman scattering

Abstract

Ramsey interferometry provides a natural way to determine the coherence time of most qubit systems. Recent experiments on quantum dots however, demonstrated that dynamical nuclear spin polarization can strongly influence the measurement process, making it difficult to extract the $T_2^{\ast }$ coherence time using optical Ramsey pulses. Here, we demonstrate an alternative method for spin coherence measurement that is based on first-order coherence of photons generated in spin-flip Raman scattering. We show that if a quantum emitter is driven by a weak monochromatic laser, Raman coherence is determined exclusively by spin coherence, allowing for a direct determination of spin $T_2^{\ast }$ time. When combined with coherence measurements on Rayleigh scattered photons, our technique enables us to identify coherent and incoherent contributions to resonance fluorescence, and to minimize the latter. We verify the validity of our technique by comparing our results to those determined from Ramsey interferometry for electron and heavy-hole spins.

arXiv comment8 pages, 6 figures

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Cited by in corpus (11)

• Recent advances in hole-spin qubits
• Improving a solid-state qubit through an engineered mesoscopic environment
• Coherent Dynamics in Quantum Emitters under Dichromatic Excitation
• Towards a source of multi-photon entangled states for linear optical quantum computing
• Coherence of a dynamically decoupled quantum-dot hole spin
• Fundamental Limits to Coherent Photon Generation with Solid-State Atomlike Transitions
• Controllable photonic time-bin qubits from a quantum dot
• Frequency-encoded linear cluster states with coherent Raman photons
• Multi-dimensional photonic states from a quantum dot
• First-order coherence of light emission from inhomogeneously broadened mesoscopic ensembles
• Direct high resolution resonant Raman scattering measurements of InAs quantum dot dynamic nuclear spin polarization states