26 research outputs found
Loss-enabled sub-Poissonian light generation in a bimodal nanocavity
We propose an implementation of a source of strongly sub-Poissonian light in
a system consisting of a quantum dot coupled to both modes of a lossy bimodal
optical cavity. When one mode of the cavity is resonantly driven with coherent
light, the system will act as an efficient photon number filter, and the
transmitted light will have a strongly sub-Poissonian character. In addition to
numerical simulations demonstrating this effect, we present a physical
explanation of the underlying mechanism. In particular, we show that the effect
results from an interference between the coherent light transmitted through the
resonant cavity and the super-Poissonian light generated by photon-induced
tunneling. Peculiarly, this effect vanishes in the absence of the cavity loss
Phonon-mediated coupling between quantum dots through an off-resonant microcavity
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 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
Complete Coherent Control of a Quantum Dot Strongly Coupled to a Nanocavity
Strongly coupled quantum dot-cavity systems provide a non-linear
configuration of hybridized light-matter states with promising quantum-optical
applications. Here, we investigate the coherent interaction between strong
laser pulses and quantum dot-cavity polaritons. Resonant excitation of
polaritonic states and their interaction with phonons allow us to observe
coherent Rabi oscillations and Ramsey fringes. Furthermore, we demonstrate
complete coherent control of a quantum dot-photonic crystal cavity based
quantum-bit. By controlling the excitation power and phase in a two-pulse
excitation scheme we achieve access to the full Bloch sphere. Quantum-optical
simulations are in good agreement with our experiments and provide insight into
the decoherence mechanisms
Ultrafast polariton-phonon dynamics of strongly coupled quantum dot-nanocavity systems
We investigate the influence of exciton-phonon coupling on the dynamics of a
strongly coupled quantum dot-photonic crystal cavity system and explore the
effects of this interaction on different schemes for non-classical light
generation. By performing time-resolved measurements, we map out the
detuning-dependent polariton lifetime and extract the spectrum of the
polariton-to-phonon coupling with unprecedented precision. Photon-blockade
experiments for different pulse-length and detuning conditions (supported by
quantum optical simulations) reveal that achieving high-fidelity photon
blockade requires an intricate understanding of the phonons' influence on the
system dynamics. Finally, we achieve direct coherent control of the polariton
states of a strongly coupled system and demonstrate that their efficient
coupling to phonons can be exploited for novel concepts in high-fidelity single
photon generation
Coherent generation of nonclassical light on chip via detuned photon blockade
The on-chip generation of non-classical states of light is a key-requirement
for future optical quantum hardware. In solid-state cavity quantum
electrodynamics, such non-classical light can be generated from self-assembled
quantum dots strongly coupled to photonic crystal cavities. Their anharmonic
strong light-matter interaction results in large optical nonlinearities at the
single photon level, where the admission of a single photon into the cavity may
enhance (photon-tunnelling) or diminish (photon-blockade) the probability for a
second photon to enter the cavity. Here, we demonstrate that detuning the
cavity and QD resonances enables the generation of high-purity non-classical
light from strongly coupled systems. For specific detunings we show that not
only the purity but also the efficiency of single-photon generation increases
significantly, making high-quality single-photon generation by photon-blockade
possible with current state-of-the-art samples.Comment: Phys. Rev. Lett. in pres
Proposed Coupling of an Electron Spin in a Semiconductor Quantum Dot to a Nanosize Optical Cavity
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 GHz.Comment: 6 figure