7 research outputs found
Coherent storage and manipulation of broadband photons via dynamically controlled Autler-Townes splitting
The coherent control of light with matter, enabling storage and manipulation
of optical signals, was revolutionized by electromagnetically induced
transparency (EIT), which is a quantum interference effect. For strong
electromagnetic fields that induce a wide transparency band, this quantum
interference vanishes, giving rise to the well-known phenomenon of
Autler-Townes splitting (ATS). To date, it is an open question whether ATS can
be directly leveraged for coherent control as more than just a case of "bad"
EIT. Here, we establish a protocol showing that dynamically controlled
absorption of light in the ATS regime mediates coherent storage and
manipulation that is inherently suitable for efficient broadband quantum memory
and processing devices. We experimentally demonstrate this protocol by storing
and manipulating nanoseconds-long optical pulses through a collective spin
state of laser-cooled Rb atoms for up to a microsecond. Furthermore, we show
that our approach substantially relaxes the technical requirements intrinsic to
established memory schemes, rendering it suitable for broad range of platforms
with applications to quantum information processing, high-precision
spectroscopy, and metrology.Comment: 14 pages with 6 figures; 3 pages supplementary info with 2
supplementary figure
Single-photon-level light storage in cold atoms using the Autler-Townes splitting protocol
Broadband spin-photon interfaces for long-lived storage of photonic quantum
states are key elements for quantum information technologies. Yet, reliable
operation of such memories in the quantum regime is challenging due to photonic
noise arising from technical and/or fundamental limitations in the
storage-and-recall processes controlled by strong electromagnetic fields. Here,
we experimentally implement a single-photon-level spin-wave memory in a
laser-cooled Rubidium gas, based on the recently proposed Autler-Townes
splitting (ATS) protocol. We demonstrate storage of 20-ns-long laser pulses,
each containing an average of 0.1 photons, for 200 ns with an efficiency of
and signal-to-noise ratio above 30. Notably, the robustness of ATS
spin-wave memory against motional dephasing allows for an all-spatial filtering
of the control-field noise, yielding an ultra-low unconditional noise
probability of , without the complexity of spectral
filtering. These results highlight that broadband ATS memory in ultracold atoms
is a preeminent option for storing quantum light.Comment: 6 pages, 4 figure
Bright quantum photon sources from a topological Floquet resonance
Entanglement, a fundamental concept in quantum mechanics, plays a crucial
role as a valuable resource in quantum technologies. The practical
implementation of entangled photon sources encounters obstacles arising from
imperfections and defects inherent in physical systems and microchips,
resulting in a loss or degradation of entanglement. The topological photonic
insulators, however, have emerged as promising candidates, demonstrating an
exceptional capability to resist defect-induced scattering, thus enabling the
development of robust entangled sources. Despite their inherent advantages,
building bright and programmable topologically protected entangled sources
remains challenging due to intricate device designs and weak material
nonlinearity. Here we present an advancement in entanglement generation
achieved through a non-magnetic and tunable resonance-based anomalous Floquet
insulator, utilizing an optical spontaneous four-wave mixing process. Our
experiment demonstrates a substantial enhancement in entangled photon pair
generation compared to devices reliant solely on topological edge states and
outperforming trivial photonic devices in spectral resilience. This work marks
a step forward in the pursuit of defect-robust and bright entangled sources
that can open avenues for the exploration of cascaded quantum devices and the
engineering of quantum states. Our result could lead to the development of
resilient quantum sources with potential applications in quantum technologies.Comment: 20 pages, 10 figure
Quantum enhanced probing of multilayered-samples
Quantum sensing exploits quantum phenomena to enhance the detection and
estimation of classical parameters of physical systems and biological entities,
particularly so as to overcome the inefficiencies of its classical
counterparts. A particularly promising approach within quantum sensing is
Quantum Optical Coherence Tomography which relies on non-classical light
sources to reconstruct the internal structure of multilayered materials.
Compared to traditional classical probing, Quantum Optical Coherence Tomography
provides enhanced-resolution images and is unaffected by even-order dispersion.
One of the main limitations of this technique lies in the appearance of
artifacts and echoes, i.e. fake structures that appear in the coincidence
interferogram, which hinder the retrieval of information required for
tomography scans. Here, by utilizing a full theoretical model, in combination
with a fast genetic algorithm to post-process the data, we successfully extract
the morphology of complex multilayered samples and thoroughly distinguish real
interfaces, artifacts, and echoes. We test the effectiveness of the model and
algorithm by comparing its predictions to experimentally-generated
interferograms through the controlled variation of the pump wavelength. Our
results could potentially lead to the development of practical high-resolution
probing of complex structures and non-invasive scanning of photo-degradable
materials for biomedical imaging/sensing, clinical applications, and materials
science