336 research outputs found
Single-photon emission via Raman scattering from the levels with partially resolved hyperfine structure
The probability of emission of a single photon via Raman scattering of laser
pulse on the three-level - type atom in microcavity is studied. The
duration of the pulse is considered to be short enough, so that the hyperfine
structure of the upper level remains totally unresolved, while that of the
lower level is totally resolved. The coherent laser pulse is assumed to be in
resonance with the transition between one hyperfine structure component of the
lower atomic level and all hyperfine structure components of the upper level,
while the quantized cavity field is assumed to be in resonance with the
transition between the other hyperfine structure component of the lower level
and all components of the upper one. The dependence of the photon emission
probability on the mutual orientation of polarization vectors of the cavity
mode and of the coherent laser pulse is analyzed. Particularly, the case is
investigated, when the total electronic angular momentum of the lower atomic
level equals 1/2, which is true for the ground states of alkali atoms employed
in the experiments on deterministic single photon emission. It is shown, that
in this case the probability of photon emission equals zero for collinear
polarizations of the photon and of the laser pulse, and the probability obtains
its maximum value, when the angle between their polarizations equals 60
degrees.Comment: 5 pages, 3 figure
Experimental investigation of amplitude and phase quantum correlations in a type II OPO above threshold: from the non-degenerate to the degenerate operation
We describe a very stable type II optical parametric oscillator operated
above threshold which provides 9.7 0.5 dB (89%) of quantum noise
reduction on the intensity difference of the signal and idler modes. We also
report the first experimental study by homodyne detection of the generated
bright two-mode state in the case of frequency degenerate operation obtained by
introducing a birefringent plate inside the optical cavity
Remote preparation of continuous-variable qubits using loss-tolerant hybrid entanglement of light
Transferring quantum information between distant nodes of a network is a key
capability. This transfer can be realized via remote state preparation where
two parties share entanglement and the sender has full knowledge of the state
to be communicated. Here we demonstrate such a process between heterogeneous
nodes functioning with different information encodings, i.e., particle-like
discrete-variable optical qubits and wave-like continuous-variable ones. Using
hybrid entanglement of light as a shared resource, we prepare arbitrary
coherent-state superpositions controlled by measurements on the distant
discrete-encoded node. The remotely prepared states are fully characterized by
quantum state tomography and negative Wigner functions are obtained. This work
demonstrates a novel capability to bridge discrete- and continuous-variable
platforms
Reversible Quantum Interface for Tunable Single-sideband Modulation
Using Electromagnetically Induced Transparency (EIT) in a Cesium vapor, we
demonstrate experimentally that the quantum state of a light beam can be mapped
into the long lived Zeeman coherences of an atomic ground state. Two
non-commuting variables carried by light are simultaneously stored and
subsequentely read-out, with no noise added. We compare the case where a
tunable single sideband is stored independently of the other one to the case
where the two symmetrical sidebands are stored using the same EIT transparency
window.Comment: 4 pages, 6 figure
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