274 research outputs found
Geometrically-controlled polarisation processing in an integrated photonic platform
The polarisation of light is a powerful and widely used degree of freedom to
encode information, both in classical and quantum applications. In particular,
quantum information technologies based on photons are being revolutionised by
the use of integrated photonic circuits. It is therefore very important to be
able to manipulate the polarisation of photons in such circuits. We
experimentally demonstrate the fabrication by femtosecond laser micromachining
of components such as polarisation insensitive or polarising directional
couplers, operating at 1550 nm wavelength, where the two opposite behaviours
are achieved just by controlling the geometric layout of the photonic circuits,
being the waveguides fabricated with the same irradiation recipe. We expect to
employ this approach in complex integrated photonic devices, capable of a full
control of the photons polarisation for quantum cryptography, quantum
computation and quantum teleportation experiments.Comment: 9 pages, 7 figure
Fast Escape from Quantum Mazes in Integrated Photonics
Escaping from a complex maze, by exploring different paths with several
decision-making branches in order to reach the exit, has always been a very
challenging and fascinating task. Wave field and quantum objects may explore a
complex structure in parallel by interference effects, but without necessarily
leading to more efficient transport. Here, inspired by recent observations in
biological energy transport phenomena, we demonstrate how a quantum walker can
efficiently reach the output of a maze by partially suppressing the presence of
interference. In particular, we show theoretically an unprecedented improvement
in transport efficiency for increasing maze size with respect to purely quantum
and classical approaches. In addition, we investigate experimentally these
hybrid transport phenomena, by mapping the maze problem in an integrated
waveguide array, probed by coherent light, hence successfully testing our
theoretical results. These achievements may lead towards future bio-inspired
photonics technologies for more efficient transport and computation.Comment: 13 pages, 10 figure
Fractional Bloch oscillations in photonic lattices
Bloch oscillations, the oscillatory motion of a quantum particle in a
periodic potential, are one of the most fascinating effects of coherent quantum
transport. Originally studied in the context of electrons in crystals, Bloch
oscillations manifest the wave nature of matter and are found in a wide variety
of different physical systems. Here we report on the first experimental
observation of fractional Bloch oscillations, using a photonic lattice as a
model system of a two-particle extended Bose-Hubbard Hamiltonian. In our
photonic simulator, the dynamics of two correlated particles hopping on a
one-dimensional lattice is mapped into the motion of a single particle in a
two-dimensional lattice with engineered defects and mimicked by light transport
in a square waveguide lattice with a bent axis
Symmetric polarization insensitive directional couplers fabricated by femtosecond laser waveguide writing
We study analytically the polarization behaviour of directional couplers
composed of birefringent waveguides, showing that they can induce polarization
transformations that depend on the specific input-output path considered. On
the basis of this study, we propose and demonstrate experimentally, by
femtosecond laser writing, directional couplers that are free from this problem
and also yield a polarization independent power-splitting ratio. More in
detail, we devise two different approaches to realize such devices: the first
one is based on local birefringence engineering, while the second one exploits
ultra-low birefringence waveguides obtained by thermal annealing
Benchmarking integrated photonic architectures
Photonic platforms represent a promising technology for the realization of
several quantum communication protocols and for experiments of quantum
simulation. Moreover, large-scale integrated interferometers have recently
gained a relevant role for restricted models of quantum computing, specifically
with Boson Sampling devices. Indeed, various linear optical schemes have been
proposed for the implementation of unitary transformations, each one suitable
for a specific task. Notwithstanding, so far a comprehensive analysis of the
state of the art under broader and realistic conditions is still lacking. In
the present work we address this gap, providing in a unified framework a
quantitative comparison of the three main photonic architectures, namely the
ones with triangular and square designs and the so-called fast transformations.
All layouts have been analyzed in presence of losses and imperfect control over
the reflectivities and phases of the inner structure. Our results represent a
further step ahead towards the implementation of quantum information protocols
on large-scale integrated photonic devices.Comment: 10 pages, 6 figures + 2 pages Supplementary Informatio
Photonic realization of the quantum Rabi model
We realize a photonic analog simulator of the quantum Rabi model, based on
light transport in femtosecond-laser-written waveguide superlattices, which
provides an experimentally accessible testbed to explore the physics of
light-matter interaction in the deep strong coupling regime. Our optical
setting enables to visualize dynamical regimes not yet accessible in cavity or
circuit quantum electrodynamics, such as bouncing of photon number wave packets
in parity chains of Hilbert space
All-optical non-Markovian stroboscopic quantum simulator
An all-optical scheme for simulating non-Markovian evolution of a quantum
system is proposed. It uses only linear optics elements and by controlling the
system parameters allows one to control the presence or absence of information
backflow from the environment. A sufficient and necessary condition for the
non-Markovianity of our channel based on Gaussian inputs is proved. Various
criteria for detecting non-Markovianity are also investigated by checking the
dynamical evolution of the channel.Comment: 7 figures. Typos are corrected and new reference is adde
Two-particle bosonic-fermionic quantum walk via 3D integrated photonics
Quantum walk represents one of the most promising resources for the
simulation of physical quantum systems, and has also emerged as an alternative
to the standard circuit model for quantum computing. Up to now the experimental
implementations have been restricted to single particle quantum walk, while
very recently the quantum walks of two identical photons have been reported.
Here, for the first time, we investigate how the particle statistics, either
bosonic or fermionic, influences a two-particle discrete quantum walk. Such
experiment has been realized by adopting two-photon entangled states and
integrated photonic circuits. The polarization entanglement was exploited to
simulate the bunching-antibunching feature of non interacting bosons and
fermions. To this scope a novel three-dimensional geometry for the waveguide
circuit is introduced, which allows accurate polarization independent
behaviour, maintaining a remarkable control on both phase and balancement.Comment: 4 pages, 5 figures + supplementary informatio
Selective plane illumination microscopy on a chip
Selective plane illumination microscopy can image biological samples at a high spatiotemporal resolution. Complex sample preparation and system alignment normally limit the throughput of the method. Using femtosecond laser micromachining, we created an integrated optofluidic device that allows obtaining continuous flow imaging, three-dimensional reconstruction and high-throughput analysis of large multicellular spheroids at a subcellular resolution
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