Stark-shift modulation absorption spectroscopy of single quantum dots

Alén, Benito; Bickel, F.; Karraï, K.; Warburton, Richard J.; Petroff, P. M.

doi:10.1063/1.1609243

Cited by 146 publications

(91 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The technique allows mapping of QD transitions with a resolution given by the excitation laser, which is in the MHz regime in our case. This cavity-enhanced spectroscopy technique adds an important tool to the repertoire for resonant single quantum dot spectroscopy [14][15][16][17]. Resonance fluorescence from a QD in a cavity was previously reported in a planar optical cavity [18]; however, the excitation geometry used in Ref.…”

mentioning

confidence: 99%

Resonant Excitation of a Quantum Dot Strongly Coupled to a Photonic Crystal Nanocavity

et al. 2010

View full text Add to dashboard Cite

We describe the resonant excitation of a single quantum dot that is strongly coupled to a photonic crystal nanocavity. The cavity represents a spectral window for resonantly probing the optical transitions of the quantum dot. We observe narrow absorption lines attributed to the single and biexcition quantum dot transitions and measure antibunched population of the detuned cavity mode [g ð2Þ ð0Þ ¼ 0:19]. DOI: 10.1103/PhysRevLett.104.073904 PACS numbers: 42.70.Qs, 42.50.Ct, 42.50.Dv, 78.67.Hc Photonic nanocavities coupled to semiconductor quantum dots (QDs) are becoming well developed systems for studying cavity quantum electrodynamics and constructing devices for quantum information processing. Recent experiments have found remarkably strong emission at the cavity resonance even when the QD emission was far detuned [1][2][3][4]. In these experiments the QD was pumped through the wetting layer, which allows for multiexciton processes through the wetting layer or a multi-QD effective continuum. In contrast, in this Letter we investigate the resonant excitation of an InAs quantum dot that is strongly coupled to a photonic crystal cavity. We show that the resonantly excited QD emits efficiently through the cavity mode and model the interaction by a phonon-mediated dephasing model [5][6][7]. In this experiment, the cavity signal effectively becomes a spectrally separated readout channel for high-resolution single quantum dot spectroscopy. In addition, because the QD is resonantly excited, the antibunched cavity emission has the potential for low timing jitter and high photon indistinguishability [7,8].The optical system consists of a photonic crystal (PC) cavity fabricated in a 160-nm thick GaAs membrane which contains a central layer of self-assembled InGaAs QDs. As shown in Fig. 1(c), we employ a grating-integrated cavity (GIC) design [9], based on a linear three-hole defect cavity [10]. The GIC design incorporates a second-order grating around the cavity, as seen in the perturbations in Figs. 1(b) and 1(c), which couple plane waves with low in-plane k vectors with the cavity mode.We first characterize the QD-cavity system by its photoluminescence (PL) under nonresonant excitation at a temperature between 10 and 50 K. A continuous-wave (cw) laser at p ¼ 860 nm excites electron-hole pairs which can relax through a phonon-mediated process into radiative levels of the QD [ Fig. 1(d)]. Figure 1(e) plots the anticrossing between the QD-like and cavitylike states. Fits to the anticrossing spectra yield the system parameters summarized in Fig. 1(d).We measure the reflection of the cavity by the crosspolarized reflectivity method illustrated in Fig. 1(a), as in our earlier work [11]. The cavity is polarized at 45 to the vertical input beam, while the reflection is detected in the horizontal polarization on a charge coupled device (CCD). The table lists the system parameters derived from the measurements, where g, , Ã are the vacuum Rabi frequency, cavity field decay rate, and dipole dephasing rate, respectively. The dip...

show abstract

mentioning

confidence: 99%

Resonant Excitation of a Quantum Dot Strongly Coupled to a Photonic Crystal Nanocavity

et al. 2010

View full text Add to dashboard Cite

show abstract

“…In fact, the coherent control of an exciton wave function in a quantum dot, namely the manipulation of the relative phases of the eigenstates in a quantum superposition, is experimentally achievable [23]. Also in the quantum dots scenario one can tune the energy levels by means of the Stark effect with typical shifts ∼1-10 GHz [24,25], so that the required conditions for qubit coherent manipulations could be accomplished. These features make quantum dots incorporated in a PBG material good candidates for the implementation of various schemes for quantum computation and coherent information processing.…”

mentioning

confidence: 99%

Entanglement trapping in structured environments

et al. 2008

View full text Add to dashboard Cite

The entanglement dynamics of two independent qubits each embedded in a structured environment under conditions of inhibition of spontaneous emission is analyzed, showing entanglement trapping. We demonstrate that entanglement trapping can be used efficiently to prevent entanglement sudden death. For the case of realistic photonic band-gap materials, we show that high values of entanglement trapping can be achieved. This result is of both fundamental and applicative interest since it provides a physical situation where the entanglement can be preserved and manipulated, e.g. by Stark-shifting the qubit transition frequency outside and inside the gap.PACS numbers: 03.67. Mn, 03.65.Yz, 71.55.Jv Entanglement preservation is an important challenge in quantum information and computation technologies [1]. Realistic quantum systems are affected by decoherence and entanglement losses because of the unavoidable interaction with their environments [2]. For example in Markovian (memoryless) environments, in spite of an exponential decay of the single qubit coherence, the entanglement between two qubits may completely disappear at a finite time [3,4]. This phenomenon, known as "entanglement sudden death" and proven to occur in a quantum optics experiment [5], in turn limits the time when entanglement could be exploited for practical purposes. It is therefore of interest to examine the possibility to preserve entanglement. In the case of environments with memory (non-Markovian), such as imperfect cavities supporting a mode resonant with the atomic transition frequency, revivals of two-qubit entanglement have been found [6,7,8]. These revivals, although effectively extending the possible usage time of entanglement, decrease with time and eventually disappear after a certain critical time. Moreover, when the qubits interact with a common environment, it has been shown that entanglement can be preserved by means of the quantum Zeno effect [8].In this paper we continue the investigation on physical systems and physical effects that may lead to effective long time entanglement protection. Since entanglement evolution and population decay have been previously shown to be related [7], one is led to investigate situations where population trapping occurs. This can happen in structured environments where the density of states presents a dip which can inhibit spontaneous emission in the region of the dip [9]. Among realistic physical situations, this effect is known to occur in photonic band-gap (PBG) materials [10]. Entanglement can be generated when a pair of atoms near-resonantly coupled to the edge of a PBG present direct dipole-dipole interaction [11]. On the other hand, a way to produce entangled independent atoms in PBG materials is to consider a three-dimensional photonic crystal single-mode cavity with a sufficiently high-quality Q factor where Rydberg atoms can freely travel through the connected void regions [12]. The atoms exchange photons with the cavity, represented by a single defect mode of the crystal resonant with t...

show abstract

“…We first characterized the QD with a single beam voltage modulation absorption experiment [15,18]. We set the gate voltage at the edge of the trion charge plateau, where the optical pumping of the electron spin effect is suppressed [15,16].…”

mentioning

confidence: 99%