Search results for " BIST"
showing 10 items of 34 documents
Mechanical Bistable Structures for Microrobotics and Mesorobotics from Microfabrication to Additive Manufacturing
2018
International audience; The use of mechanical bistable structures in the design of microrobots and mesorobots has many advantages especially for flexible robotic structures. However, depending on the fabrication technology used, the adequacy of theoretical and experimental mechanical behaviors can vary widely. In this paper, we present the manufacturing results of bistable structures made with two extensively used contemporary technologies: MEMS and FDM additive manufacturing. Key issues of these fabrication technologies are discussed in the context of microrobotics and mesorobotics applications.
Recent Advances of Spin Crossover Research
2004
Thermal spin transition (spin crossover), one of the most fascinating dynamic electronic structure phenomena occurring in coordination compounds of third row transition metal ions, mostly of iron(II), iron(III) and cobalt(II) with critical ligand field strengths competing with the spin pairing energy, has attracted increasing attention by many research groups. One of the reasons is the promising potential for practical applications. In this chapter we intend to cover essential recent work, primarily accomplished within the European research network on "Thermal and Optical Switching of Molecular Spin States (TOSS)". New spin crossover compounds and their thermal spin transition behaviour, al…
Observation of a nonlinear microfiber resonator
2008
Measurements of the intensity transfer function of a silica microfiber resonator are shown to follow a wide variety of hysteresis cycles, depending on the cavity detuning and the scanning frequency of the range of input powers. We attribute these observations to a nonlinear phase shift of thermal origin and provide a simple model that reproduces well our measurements. The response time is found to be around 0.6 ms.
Non-Linear Optical Properties of Hybridized Surface Plasmon Polaritonic Crystals: Observation of Optical Bistability
2007
Summary form only given. The use of surface plasmons (SP) is recognized as being central to the development of nanoscale assemblies of photonic and opto-electronic devices. This is motivated by the spatially confined nature of these electromagnetic waves as well as their resonant behavior. Amongst plasmonic supporting structures, surface plasmonic crystals (SPCs) draw particular interest because of their tailored optical properties. A geometry common to SPCs consists in a periodic arrangement of holes or slits in a metal film. Their complex optical response is then governed by coherent interactions between Bloch modes at the film's interfaces and modes supported by the holes or slits. These…
Photophysical Properties of Discotic Dibenzopyrenes
1997
Abstract The photophysical properties of three discogenic dibenzopyrenes substituted by eight pentyloxy (O5DPB), heptyloxy (O7DBPP) or decyloxy (O10DBP) side chains are studied in solution and thin films. It is shown that the absorption and fluorescence spectra of the columnar mesophases are clearly distinguishable from those of the corresponding crystalline phases, allowing the study of phase transitions. Thus, it is found that the shorter the lateral chain length, the slower the crystallisation process. For O5DBP, the supercooled mesophase is stable over a period of at least one year; it crystallises after cooling below the glassy transition. Such a behaviour gives rise to temperature con…
Experimental demonstration of bistable phase locking in a photorefractive oscillator
2012
We report experimental evidence of bistable phase locking in nonlinear optics, in particular, in a photorefractive oscillator emitting in few transverse modes. Bistable phase locking is a recently proposed method for converting a laserlike system, which is phase invariant, into a phase-bistable one by injecting a suitable spatially modulated monochromatic beam, resonant with the laser emission, into the optical cavity. We experimentally demonstrate that the emission on the fundamental TEM00 mode becomes phase bistable by injection of a beam with the shape of the TEM10 mode with appropriate frequency, in accordance with recent theoretical predictions [K. Staliunas et al., Phys. Rev. A 80, 02…
Optical Bistability and Switching in Oppositely Directed Coupler
2016
We report the optical bistability in two core oppositely directed coupler with negative index material channel. Using Langrangian variational method and Jacobi elliptic functions, we construct the solutions of the coupled nonlinear Schrodinger equations. The bistability arises due to the effective feedback mechanism as a result of opposite directionality of the phase velocity and energy flow in the negative index material channel. We report the various ways to control and manipulate the bistability threshold and hysteresis loop, which could be useful in the design and development of fast and low-threshold optical switches.
Bistable phase locking of a laser via monochromatic signal injection
2009
In free running lasers the field phase is not fixed and any value possible value is equally likely (invariant), but can be locked to an external reference by injecting a monochromatic signal field into the cavity. In this way the phase of the slave laser locks to a single value resulting in a monostable phase locking. It could be however of practical interest that the laser field be locked not to a single value but to two different possible values, hence the name bistable phase locking.
Bistable phase locking in a low fresnel number nondegenerate optical oscillator with injected signal
2011
Degenerate four-wave mixing oscillators are phase-bistable cavities. In such systems, above the oscillation threshold, two equivalent states, of equal intensities but opposite phases are generated. This phase bistability extends over the whole range of stable emission, unlike the intensity bistability (in, e.g. a saturable absorber cavity) that exits in a limited range of injection. When the cavity Fresnel number is large different patches of the beam transverse section can have different phases and a pattern forms. Basic patterns here are phase fronts (or domain walls), which are 1D structures separating regions with opposite phase that manifest as dark lines (as the phase jumps by p acros…
Cavity solitons in lasers with spatially modulated injected signal
2009
The injection of a monochromatic signal into a laser is a well-known technique for locking the laser phase to that of the injection. Some years ago another type of injection, called rocking [1,2], was introduced to render the laser phase-locking bistable. Rocking consists of the modulation of the amplitude injection so that its sign changes periodically, or even randomly [3], in time. Here we present an alternative to rocking that leads to the same type of behaviour, namely the appearance of bistable phase locking and, in the case of large Fresnel number lasers, to stable (phase bistable) cavity solitons and extended patterns. The new type of injection we present here is monochromatic, unli…