TY  - JOUR
A1  - Kasprzak, J.
A1  - Sivalertporn, K.
A1  - Albert, F.
A1  - Schneider, C.
A1  - Höfling, S.
A1  - Kamp, M.
A1  - Forchel, A.
A1  - Muljarov, E. A.
A1  - Langbein, W.
T1  - Coherence dynamics and quantum-to-classical crossover in an exciton-cavity system in the quantum strong coupling regime
JF  - New Journal of Physics
N2  - Interaction between light and matter generates optical nonlinearities, which are particularly pronounced in the quantum strong coupling regime. When a single bosonic mode couples to a single fermionic mode, a Jaynes-Cummings (JC) ladder is formed, which we realize here using cavity photons and quantum dot excitons. We measure and model the coherent anharmonic response of this strongly coupled exciton-cavity system at resonance. Injecting two photons into the cavity, we demonstrate a \(\sqrt 2\) larger polariton splitting with respect to the vacuum Rabi splitting. This is achieved using coherent nonlinear spectroscopy, specifically four-wave mixing, where the coherence between the ground state and the first (second) rung of the JC ladder can be interrogated for positive (negative) delays. With increasing excitation intensity and thus rising average number of injected photons, we observe spectral signatures of the quantum-to-classical crossover of the strong coupling regime.
KW  - Jaynes-Cummings ladder
KW  - spectral interferometry
KW  - photon
KW  - dot
KW  - spectroscopy
KW  - oscillations
KW  - microcavity
KW  - resonance
KW  - light
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-123005
SN  - 1367-2630
VL  - 15
IS  - 045013
ER  - 
TY  - JOUR
A1  - Hopfmann, C.
A1  - Albert, F.
A1  - Schneider, C.
A1  - Höfling, S.
A1  - Kamp, M.
A1  - Forchel, A.
A1  - Kanter, I.
A1  - Reizenstein, S.
T1  - Nonlinear emission characteristics of quantum dot-micropillar lasers in the presence of polarized optical feedback
JF  - New Journal of Physics
N2  - We report on electrically pumped quantum dot-microlasers in the presence of polarized self-feedback. The high-\(\beta\) microlasers show two orthogonal, linearly polarized emission modes which are coupled via the common gain medium. This coupling is explained in terms of gain competition between the two lasing modes and leads to distinct differences in their input-output characteristics. By applying polarized self-feedback via an external mirror, we are able to control the laser characteristics of the emission modes in terms of the output power, the coherence time and the photon statistics. We find that linearly polarized self-feedback stabilizes the lasing of a given mode, while cross-polarized feedback between the two modes reduces strongly the intensity of the other emission mode showing particular high-intensity fluctuations and even super-thermal values of the photon autocorrelation function \(g^{(2)} (\tau)\) at zero delay. Measurements of \(g^{(2)} (\tau)\) under external feedback also allow us to detect revival peaks associated with the round trip time of the external cavity. Analyzing the damping and shape of the \(g^{(2)} (\tau)\) revival peaks by a phenomenological model provides us insight into the underlying physics such as the effective exciton lifetime and gain characteristics of the quantum dots in the active region of these microlasers.
KW  - semiconductor lasers
KW  - coherence
KW  - system
KW  - gain
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-123127
SN  - 1367-2630
VL  - 15
IS  - 025030
ER  - 
TY  - JOUR
A1  - Braun, T.
A1  - Schneider, C.
A1  - Maier, S.
A1  - Igusa, R.
A1  - Iwamoto, S.
A1  - Forchel, A.
A1  - Höfling, S.
A1  - Arakawa, Y.
A1  - Kamp, M.
T1  - Temperature dependency of the emission properties from positioned In(Ga)As/GaAs quantum dots
JF  - AIP Advances
N2  - In this letter we study the influence of temperature and excitation power on the emission linewidth from site-controlled InGaAs/GaAs quantum dots grown on nanoholes defined by electron beam lithography and wet chemical etching. We identify thermal electron activation as well as direct exciton loss as the dominant intensity quenching channels. Additionally, we carefully analyze the effects of optical and acoustic phonons as well as close-by defects on the emission linewidth by means of temperature and power dependent micro-photoluminescence on single quantum dots with large pitches. (C) 2014 Author(s).
KW  - GAAS
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115448
SN  - 2158-3226
VL  - 4
IS  - 9
ER  -