Received 15 January 2013DOI:https://doi.org/10.1103/PhysRevB.87.079907©2013 American Physical Society

We propose a scheme to efficiently couple a single quantum dot electron spin to an optical nano-cavity, which enables us to simultaneously benefit from a cavity as an efficient photonic interface, as well as to perform high fidelity (nearly 100%) spin initialization and manipulation achievable in bulk semiconductors. Moreover, the presence of the cavity speeds up the spin initialization process beyond the GHz range.

Submitted for the MAR07 Meeting of The American Physical Society Spin Coherence Modulated Trion Transitions and Probabilistic Initialization in Charged Semiconductor Quantum Dots1 YANWEN WU, ERIK KIM, XIAODONG XU, JUN CHENG, DUNCAN STEEL, The H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109, SOPHIA ECONOMOU, LU SHAM, Department of Physics, University of California, San Diego, La Jolla, California, 92093-0319, DAN GAMMON, ALAN BRACKER, The Naval Research Laboratory, Washington D.C. 20375 — The presence of symmetry breaking in a three-level Λ system consisting of two spin ground states and a charged exciton (trion) state leads to new features, where the population excited to the trion state is modulated by the spin coherence. This phenomenon is due to the unique semiconductor environment of the quantum dot (QD) system, which allows for two simultaneously orthogonal spinor axes. In addition, the polarization dependent excitations due to the double spinor axes of the system can be utilized to create a net spin from a completely mixed spin state, which is impossible to achieve through unitary operation of the spin system. This result provides an important application to the practical implementation of ultrafast spin based quantum computation in the semiconductor QD system in terms of qubit initialization. 1This work was supported in part by LPS, ARO, ONR, AFOSR and NSF-FOCUS. Yanwen Wu University of Michigan Date submitted: 20 Nov 2006 Electronic form version 1.4

We theoretically study the bichromatic driving of a solid-state cavity quantum electrodynamics (QED) system as a means of probing cavity dressed state transitions and observing the coherent interaction between the system and the light field. We show that this method can enable the observation of the higher order cavity dressed states, supersplitting and ac-Stark shift in a solid-state system comprised of a quantum dot (QD) strongly coupled to a photonic crystal cavity for the on- and far off-resonant cases. For the off-resonant case, phonons mediate off-resonant coupling between the QD and the photonic resonator, a phenomenon unique to solid-state cavity QED.

We propose a scheme to efficiently couple a single quantum dot electron spin to an optical nano-cavity, which enables us to simultaneously benefit from a cavity as an efficient photonic interface, as well as to perform high fidelity (nearly 100 semiconductors. Moreover, the presence of the cavity speeds up the spin initialization process beyond GHz.

We present experimental results showing phonon-mediated coupling between two quantum dots embedded inside a photonic crystal microcavity. With only one of the dots being spectrally close to the cavity, we observe both frequency up-conversion and down-conversion of the pump light via a $\sim1.2$ THz phonon. We demonstrate this process for both weak and strong regimes of dot-cavity coupling, and provide a simple theoretical model explaining our observations.

A theoretical model for the phonon-mediated off-resonant coupling between a quantum dot and a cavity, under resonant excitation of the quantum dot, is presented. We show that the coupling is caused by electron-phonon interaction in the quantum dot and is enhanced by the cavity. We analyze recently observed resonant quantum dot spectroscopic data by our theoretical model.

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text J. Vuckovic, A. Majumdar, A. Papageorge, A. Rundquist, Y. Gong, E. Kim, and M. Bajcsy, "Opto-mechanics and quantum dot-nanocavity QED," in Frontiers in Optics 2011/Laser Science XXVII, OSA Technical Digest (Optica Publishing Group, 2011), paper FMD4. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text A. Majumdar, A. Papageorge, E. Kim, M. Bajcsy, and J. Vuckovic, "Quantum Dot Dressing Observed via Off-resonant Cavity," in Frontiers in Optics 2011/Laser Science XXVII, OSA Technical Digest (Optica Publishing Group, 2011), paper LWL4. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

We experimentally observe the effect of photo-generated carriers on the spectral diffusion of a quantum dot (QD) coupled to a photonic crystal (PC) cavity. In this system, spectral diffusion arises in part from charge fluctuations on the etched surfaces of the PC. We find that these fluctuations may be suppressed by photo-generated carriers, leading to a reduction of the measured QD linewidth by a factor of ~2 compared to the case where the photo-generated carriers are not present. This result demonstrates a possible means of countering the effects of spectral diffusion in QD-PC cavity systems and thus may be useful for quantum information applications where narrow QD linewidths are desired.

Single solid-state optical emitters have quantum mechanical properties that make them suitable for applications in information processing and sensing. Most of these quantum technologies rely on the capability to integrate the emitters in reliable solid-state optical networks. In this paper, we present integrated devices based on GaAs photonic crystals and InAs self-assembled quantum dots. These quantum networks are well suited to future optoelectronic devices operating at ultralow power levels, single-photon logic devices and quantum information processing.

A combination of a single quantum emitter (a semiconductor quantum dot) with a semiconductor optical nanocavity has been employed to demonstrate devices ranging from optical switches and modulators controlled with sub-fJ energies, to quantum sources.

Coherent interaction between a quantum dot and a resonant laser is observed through an incoherent read-out channel created by coupling to an off-resonant cavity. Under bichromatic driving of the quantum dot optical output collected from the off-resonant cavity exhibits two peaks, a signature of Rabi-side bands that matches closely with our theoretical model. The off-resonant cavity provides a convenient method for resonant quantum dot spectroscopy and quantum dot state readout.

Off-resonant quantum dot-cavity coupling is studied both experimentally and theoretically. A theoretical model is proposed to explain the observations.

The combination of a single quantum emitter (a quantum dot) and an optical nanocavity has been employed to demonstrate devices ranging from quantum sources and gates to optical switches and modulators controlled with sub-fJ energies.

We demonstrate the all-optical ultrafast manipulation and read-out of optical transitions in a single negatively charged self-assembled InAs quantum dot, an important step towards ultrafast control of the resident spin. Experiments performed at zero magnetic field show the excitation and decay of the trion (negatively charged exciton) as well as Rabi oscillations between the electron and trion states. Application of a DC magnetic field perpendicular to the growth axis of the dot enables observation of a complex quantum beat structure produced by independent precession of the ground state electron and the excited state heavy hole spins.