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Quantum fluctuations and lineshape anomaly in a high-$β$ silver-coated InP-based metallic nanolaser
Authors:
A. Koulas-Simos,
J. Buchgeister,
M. Drechsler,
T. Zhang,
K. Laiho,
G. Sinatkas,
J. Xu,
F. Lohof,
Q. Kan,
R. K. Zhang,
F. Jahnke,
C. Gies,
W. W. Chow,
C. Z. Ning,
S. Reitzenstein
Abstract:
Metallic nanocavity lasers provide important technological advancement towards even smaller integrable light sources. They give access to widely unexplored lasing physics in which the distinction between different operational regimes, like those of thermal or a coherent light emission, becomes increasingly challenging upon approaching a device with a near-perfect spontaneous-emission coupling fact…
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Metallic nanocavity lasers provide important technological advancement towards even smaller integrable light sources. They give access to widely unexplored lasing physics in which the distinction between different operational regimes, like those of thermal or a coherent light emission, becomes increasingly challenging upon approaching a device with a near-perfect spontaneous-emission coupling factor $β$. In fact, quantum-optical studies have to be employed to reveal a transition to coherent emission in the intensity fluctuation behavior of nanolasers when the input-output characteristic appears thresholdless for $β= 1$ nanolasers. Here, we identify a new indicator for lasing operation in high-$β$ lasers by showing that stimulated emission can give rise to a lineshape anomaly manifesting as a transition from a Lorentzian to a Gaussian component in the emission linewidth that dominates the spectrum above the lasing threshold.
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Submitted 14 January, 2022;
originally announced January 2022.
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Bright electrically controllable quantum-dot-molecule devices fabricated by in-situ electron-beam lithography
Authors:
Johannes Schall,
Marielle Deconinck,
Nikolai Bart,
Matthias Florian,
Martin von Helversen,
Christian Dangel,
Ronny Schmidt,
Lucas Bremer,
Frederik Bopp,
Isabell Hüllen,
Christopher Gies,
Dirk Reuter,
Andreas D. Wieck,
Sven Rodt,
Jonathan J. Finley,
Frank Jahnke,
Arne Ludwig,
Stephan Reitzenstein
Abstract:
Self-organized semiconductor quantum dots represent almost ideal two-level systems, which have strong potential to applications in photonic quantum technologies. For instance, they can act as emitters in close-to-ideal quantum light sources. Coupled quantum dot systems with significantly increased functionality are potentially of even stronger interest since they can be used to host ultra-stable s…
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Self-organized semiconductor quantum dots represent almost ideal two-level systems, which have strong potential to applications in photonic quantum technologies. For instance, they can act as emitters in close-to-ideal quantum light sources. Coupled quantum dot systems with significantly increased functionality are potentially of even stronger interest since they can be used to host ultra-stable singlet-triplet spin qubits for efficient spin-photon interfaces and for a deterministic photonic 2D cluster-state generation. We realize an advanced quantum dot molecule (QDM) device and demonstrate excellent optical properties. The device includes electrically controllable QDMs based on stacked quantum dots in a pin-diode structure. The QDMs are deterministically integrated into a photonic structure with a circular Bragg grating using in-situ electron beam lithography. We measure a photon extraction efficiency of up to (24$\pm$4)% in good agreement with numerical simulations. The coupling character of the QDMs is clearly demonstrated by bias voltage dependent spectroscopy that also controls the orbital couplings of the QDMs and their charge state in quantitative agreement with theory. The QDM devices show excellent single-photon emission properties with a multi-photon suppression of $g^{(2)}(0) = (3.9 \pm 0.5) \cdot 10^{-3}$. These metrics make the developed QDM devices attractive building blocks for use in future photonic quantum networks using advanced nanophotonic hardware.
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Submitted 8 April, 2021; v1 submitted 10 January, 2021;
originally announced January 2021.
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Carrier Dynamics in a Tunneling Injection Quantum Dot Semiconductor Optical Amplifier
Authors:
I. Khanonkin,
M. Lorke,
S. Michael,
A. K. Mishra,
J. P. Reithmaier,
F. Jahnke,
G. Eisenstein
Abstract:
The process of tunneling injection is known to improve the dynamical characteristics of quantum well and quantum dot lasers; in the latter, it also improves the temperature performance. The advantage of the tunneling injection process stems from the fact that it avoids hot carrier injection, which is a key performance-limiting factor in all semiconductor lasers. The tunneling injection process is…
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The process of tunneling injection is known to improve the dynamical characteristics of quantum well and quantum dot lasers; in the latter, it also improves the temperature performance. The advantage of the tunneling injection process stems from the fact that it avoids hot carrier injection, which is a key performance-limiting factor in all semiconductor lasers. The tunneling injection process is not fully understood microscopically and therefore it is difficult to optimize those laser structures. We present here a numerical study of the broad band carrier dynamics in a tunneling injection quantum dot gain medium in the form of an optical amplifier operating at 1.55 um. Charge carrier tunneling occurs in a hybrid state that joins the quantum dot first excited state and the confined quantum well - injection well states. The hybrid state, which is placed energetically roughly one LO phonon above the ground state and has a spectral extent of about 5 meV , dominates the carrier injection to the ground state. We calculate the dynamical response of the inversion across the entire gain spectrum following a short pulse perturbation at various wavelengths and for two bias currents. At a high bias of 200 mA, the entire spectrum exhibits gain; at 30 mA, the system exhibits a mixed gain - absorption spectrum. The carrier dynamics in the injection well is calculated simultaneously. We discuss the role of the pulse excitation wavelengths relative to the gain spectrum peak and demonstrate that the injection well responds to all perturbation wavelengths, even those which are far from the region where the tunneling injection process dominates.
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Submitted 22 July, 2018;
originally announced July 2018.
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Interplay of structural design and interaction processes in tunnel-injection semiconductor lasers
Authors:
Stephan Michael,
Michael Lorke,
Marian Cepok,
Christian Carmesin,
Frank Jahnke
Abstract:
Tunnel-injection lasers promise various advantages in comparison to conventional laser designs. In this paper, we present a theoretical analysis for the physics of the tunnel-injection process in quantum-dot based laser devices. We describe the carrier dynamics in terms of scattering between states of the coupled system consisting of injector quantum-well, tunnel-barrier, and quantum-dots. Our ana…
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Tunnel-injection lasers promise various advantages in comparison to conventional laser designs. In this paper, we present a theoretical analysis for the physics of the tunnel-injection process in quantum-dot based laser devices. We describe the carrier dynamics in terms of scattering between states of the coupled system consisting of injector quantum-well, tunnel-barrier, and quantum-dots. Our analysis demonstrates how current quantum-dot based lasers can benefit from the tunnel-injection design. We find that the often assumed LO-phonon resonance condition for the level alignment only weakly influences the injection rate of carriers into the quantum-dot states. On the other hand, our investigations show that the energetic alignment of quantum-dot and quantum-well states modifies the injection efficiency, as it controls the hybridization strength. Our description of tunneling includes the phonon-mediated and the Coulomb scattering contributions and is based on material realistic electronic structure calculations.
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Submitted 30 October, 2018; v1 submitted 10 March, 2018;
originally announced March 2018.
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Emission from quantum-dot high- microcavities: transition from spontaneous emission to lasing and the effects of superradiant emitter coupling
Authors:
S. Kreinberg,
W. W. Chow,
J. Wolters,
C. Schneider,
C. Gies,
F. Jahnke,
S. Höfling,
M. Kamp,
S. Reitzenstein
Abstract:
Measured and calculated results are presented on the emission properties of a new class of emitters operating in the cavity quantum electrodynamics regime. The structures are based on high-finesse GaAs/AlAs micropillar cavities, each with an active medium consisting of a layer of InGaAs quantum dots and distinguishing feature of having substantial fraction of spontaneous emission channeled into on…
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Measured and calculated results are presented on the emission properties of a new class of emitters operating in the cavity quantum electrodynamics regime. The structures are based on high-finesse GaAs/AlAs micropillar cavities, each with an active medium consisting of a layer of InGaAs quantum dots and distinguishing feature of having substantial fraction of spontaneous emission channeled into one cavity mode (high-beta factor). This paper shows that the usual criterion for lasing with a conventional (low-beta factor) cavity, a sharp nonlinearity in an input-output curve accompanied by noticeable linewidth narrowing, has to be reinforced by the equal-time second-order photon autocorrelation function for confirming lasing. It will also show that the equal-time second-order photon autocorrelation function is useful for recognizing superradiance, a manifestation of the correlations possible in high- microcavities operating with quantum dots. In terms of consolidating the collected data and identifying the physics underlying laser action, both theory and experiment suggest a sole dependence on intracavity photon number. Evidence for this comes from all our measured and calculated data on emission coherence and fluctuation, for devices ranging from LEDs and cavity-enhanced LEDs to lasers, lying on the same two curves: one for linewidth narrowing versus intracavity photon number and the other for g(2)(0) versus intracavity photon number.
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Submitted 13 October, 2016;
originally announced October 2016.
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Strong light-matter coupling in the presence of lasing
Authors:
Christopher Gies,
Fabian Gericke,
Paul Gartner,
Steffen Holzinger,
Caspar Hopfmann,
Tobias Heindel,
Janik Wolters,
Christian Schneider,
Matthias Florian,
Frank Jahnke,
Sven. Höfling,
Martin Kamp,
Stephan Reitzenstein
Abstract:
The regime of strong light-matter coupling is typically associated with weak excitation. With current realizations of cavity-QED systems, strong coupling may persevere even at elevated excitation levels sufficient to cross the threshold to lasing. In the presence of stimulated emission, the vacuum-Rabi doublet in the emission spectrum is modified and the established criterion for strong coupling n…
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The regime of strong light-matter coupling is typically associated with weak excitation. With current realizations of cavity-QED systems, strong coupling may persevere even at elevated excitation levels sufficient to cross the threshold to lasing. In the presence of stimulated emission, the vacuum-Rabi doublet in the emission spectrum is modified and the established criterion for strong coupling no longer applies. We provide a generalized criterion for strong coupling and the corresponding emission spectrum, which includes the influence of higher Jaynes-Cummings states. The applicability is demonstrated in a theory-experiment comparison of a few-emitter quantum-dot--micropillar laser as a particular realization of the driven dissipative Jaynes-Cummings model. Furthermore, we address the question if and for which parameters true single-emitter lasing can be achieved, and provide evidence for the coexistence of strong coupling and lasing in our system in the presence of background emitter contributions.
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Submitted 23 May, 2017; v1 submitted 17 June, 2016;
originally announced June 2016.
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Pronounced Purcell enhancement of spontaneous emission in CdTe/ZnTe quantum dots embedded in micropillar cavities
Authors:
Tomasz Jakubczyk,
Wojciech Pacuski,
Tomasz Smoleński,
Andrzej Golnik,
Matthias Florian,
Frank Jahnke,
Carsten Kruse,
Detlef Hommel,
Piotr Kossacki
Abstract:
The coupling of CdTe/ZnTe quantum dot (QD) emission to micropillar cavity eigenmodes in the weak coupling regime is demonstrated. We analyze photoluminescence spectra of QDs embedded in monolithic micropillar cavities based on Bragg mirrors which contain MgSe/ZnTe/MgTe superlattices as low-index material. The pillar emission shows pronounced cavity eigenmodes and their spectral shape is in good ag…
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The coupling of CdTe/ZnTe quantum dot (QD) emission to micropillar cavity eigenmodes in the weak coupling regime is demonstrated. We analyze photoluminescence spectra of QDs embedded in monolithic micropillar cavities based on Bragg mirrors which contain MgSe/ZnTe/MgTe superlattices as low-index material. The pillar emission shows pronounced cavity eigenmodes and their spectral shape is in good agreement with simulations. QD emission in resonance with the cavity mode is shown to be efficiently guided toward the detector and an experimental Purcell enhancement by a factor of 5.7 is determined, confirming theoretical expectations.
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Submitted 29 July, 2012;
originally announced July 2012.