Evidences of evanescent Bloch waves in Phononic Crystals

We show both experimentally and theoretically the evanescent behaviour of modes in the Band Gap (BG) of finite Phononic Crystal (PC). Based on experimental and numerical data we obtain the imaginary part of the wave vector in good agreement with the complex band structures obtained by the Extended Plane Wave Expansion (EPWE). The calculated and measured acoustic field of a localized mode out of the point defect inside the PC presents also evanescent behaviour. The correct understanding of evanescent modes is fundamental for designing narrow filters and wave guides based on Phononic Crystals with defects.Comment: 8 pages, 3 figure

Nursing Pain Assessment & Management: A 3D Interactive Simulation

In this design case, a team developed a 3D interactive simulation for nursing students and professional nurses to train and practice pain assessment and management procedures. In the simulation environment, the trainees interact with three emotionally expressive animated patients. The three patients vary in their ethnicity, age, and emotion intensity. Successful completion of the scenario requires that the trainee perform of a series of pain assessment and management tasks. The trainee is evaluated on the efficiency and appropriate sequencing of the tasks. The purpose of this paper is to describe the decisions made regarding the type of virtual patients used, the clickable objects, the pain assessment interview protocol, the visual representations in the simulation and the web portal. The paper also provides insight into the processes and steps taken during the design and development phases of this 3D interactive simulation including: the tasks analyses, motion capture, validation of the animations in the simulation, programming, and other tasks

Dynamic regimes and damping of relaxation oscillations in III-V/Si external cavity lasers

We report how external cavity IIIV/Si hybrid lasers operate in regimes of ultradamped relaxation oscillations or in turbulent and selfpulsing regimes. The different regimes are reached by detuning the lasing wavelength respect to the mirror effective reflectivity peak and are the consequence of the dispersive narrow band reflectivity of the silicon photonics mirror, the linewidth enhancement factor and fourwave mixing in the gain medium

Stealth and equiluminous materials for scattering cancellation and wave diffusion

We report a procedure to design 2-dimensional acoustic structures with prescribed scattering properties. The structures are designed from targeted properties in the reciprocal space so that their structure factors, i.e., their scattering patterns under the Born approximation, exactly follow the desired scattering properties for a set of wavelengths. The structures are made of a distribution of rigid circular cross-sectional cylinders embedded in air. We demonstrate the efficiency of the procedure by designing 2-dimensional stealth acoustic materials with broadband backscattering suppression independent of the angle of incidence and equiluminous acoustic materials exhibiting broadband scattering of equal intensity also independent of the angle of incidence. The scattering intensities are described in terms of both single and multiple scattering formalisms, showing excellent agreement with each other, thus validating the scattering properties of each material

Dynamics and tolerance to external optical feedback of III-V/Si hybrid lasers with dispersive narrowband mirror

We report how external cavity III-V/Si hybrid lasers operate in regimes of ultra-damped relaxation oscillations or in unstable regimes as consequence to the dispersive mirror, non-zero linewidth enhancement factor and four-wave mixing in the gain medium. Tolerance to external optical feedback is also discussed

Transport and Entanglement Generation in the Bose-Hubbard Model

We study entanglement generation via particle transport across a one-dimensional system described by the Bose-Hubbard Hamiltonian. We analyze how the competition between interactions and tunneling affects transport properties and the creation of entanglement in the occupation number basis. Alternatively, we propose to use spatially delocalized quantum bits, where a quantum bit is defined by the presence of a particle either in a site or in the adjacent one. Our results can serve as a guidance for future experiments to characterize entanglement of ultracold gases in one-dimensional optical lattices.Comment: 14 pages, 6 figure

Experimental validation of deep-subwavelength diffusion by acoustic metadiffusers

International audienceAn acoustic metadiffuser is a subwavelength locally resonant surface relying on slow sound propagation. Its design consists of rigidly backed slotted panels, with each slit being loaded by an array of Helmholtz resonators (HRs). Due to the slow sound properties, the effective thickness of the panel can therefore be dramatically reduced when compared to traditional diffusers made of quarter-wavelength resonators. The aim of this work is to experimentally validate the concept of metadiffusers from the scattering measurements of a specific metadiffuser design, i.e., a Quadratic Residue Metadiffuser (QRM). The experimental results reported herein are in a close agreement with analytical and numerical predictions, therefore showing the potential of metadiffusers for controlling sound diffusion at very low frequencies