10 research outputs found
Large suppression of quantum fluctuations of light from a single emitter by an optical nanostructure
We investigate the reduction of the electromagnetic field fluctuations in
resonance fluorescence from a single emitter coupled to an optical
nanostructure. We find that such hybrid system can lead to the creation of
squeezed states of light, with quantum fluctuations significantly below the
shot noise level. Moreover, the physical conditions for achieving squeezing are
strongly relaxed with respect to an emitter in free space. A high degree of
control over squeezed light is feasible both in the far and near fields,
opening the pathway to its manipulation and applications on the nanoscale with
state-of-the-art setups.Comment: 10 pages, 5 figure
Vacuum-stimulated cooling of single atoms in three dimensions
Taming quantum dynamical processes is the key to novel applications of
quantum physics, e.g. in quantum information science. The control of
light-matter interactions at the single-atom and single-photon level can be
achieved in cavity quantum electrodynamics, in particular in the regime of
strong coupling where atom and cavity form a single entity. In the optical
domain, this requires permanent trapping and cooling of an atom in a
micro-cavity. We have now realized three-dimensional cavity cooling and
trapping for an orthogonal arrangement of cooling laser, trap laser and cavity
vacuum. This leads to average single-atom trapping times exceeding 15 seconds,
unprecedented for a strongly coupled atom under permanent observation.Comment: 4 pages, 4 figure
On the suppression of the diffusion and the quantum nature of a cavity mode. Optical bistability; forces and friction in driven cavities
A new analytical method is presented here, offering a physical view of driven
cavities where the external field cannot be neglected. We introduce a new
dimensionless complex parameter, intrinsically linked to the cooperativity
parameter of optical bistability, and analogous to the scaled Rabbi frequency
for driven systems where the field is classical. Classes of steady states are
iteratively constructed and expressions for the diffusion and friction
coefficients at lowest order also derived. They have in most cases the same
mathematical form as their free-space analog. The method offers a semiclassical
explanation for two recent experiments of one atom trapping in a high Q cavity
where the excited state is significantly saturated. Our results refute both
claims of atom trapping by a quantized cavity mode, single or not. Finally, it
is argued that the parameter newly constructed, as well as the groundwork of
this method, are at least companions of the cooperativity parameter and its
mother theory. In particular, we lay the stress on the apparently more
fundamental role of our structure parameter.Comment: 24 pages, 7 figures. Submitted to J. Phys. B: At. Mol. Opt. Phy
Electromagnetically Induced Transparency with Single Atoms in a Cavity
Optical nonlinearities offer unique possibilities for the control of light
with light. A prominent example is electromagnetically induced transparency
(EIT) where the transmission of a probe beam through an optically dense medium
is manipulated by means of a control beam. Scaling such experiments into the
quantum domain with one, or just a few particles of both light and matter will
allow for the implementation of quantum computing protocols with atoms and
photons or the realisation of strongly interacting photon gases exhibiting
quantum phase transitions of light. Reaching these aims is challenging and
requires an enhanced matter-light interaction as provided by cavity quantum
electrodynamics (QED). Here we demonstrate EIT with a single atom
quasi-permanently trapped inside a high-finesse optical cavity. The atom acts
as a quantum-optical transistor with the ability to coherently control the
transmission of light through the cavity. We furthermore investigate the
scaling of EIT when the atom number is increased one by one. The measured
spectra are in excellent agreement with a theoretical model. Merging EIT with
cavity QED and single quanta of matter is likely to become the cornerstone for
novel applications, e.g. the dynamic control of the photon statistics of
propagating light fields or the engineering of Fock-state superpositions of
flying light pulses.Comment: 6 pages, 4 figure