Search results for "Resonators"
showing 10 items of 24 documents
Assembly of microparticles by optical trapping with a photonic crystal nanocavity
2012
International audience; In this work, we report the auto-assembly experiments of micrometer sized particles by optical trapping in the evanescent field of a photonic crystal nanocavity. The nanocavity is inserted inside an optofluidic cell designed to enable the real time control of the nanoresonator transmittance as well as the real time visualization of the particles motion in the vicinity of the nanocavity. It is demonstrated that the optical trap above the cavity enables the assembly of multiple particles in respect of different stable conformations.
Interferences in Locally Resonant Sonic Metamaterials Formed from Helmholtz Resonators
2019
[EN] The emergence of materials artificially designed to control the transmission of waves, generally called metamaterials, has been a hot topic in the field of acoustics for several years. The design of these metamaterials is usually carried out by overlapping different wave control mechanisms. An example of this trend is the so-called Locally Resonant Sonic Materials, being one of them the Phononic Crystals with a local resonant structure. These metamaterials are formed by sets of isolated resonators in such a way that the control of the waves is carried out by resonances and by the existence of Bragg bandgaps, which appear due to the ordered distribution of the resonators. Their use is b…
Enhancing the sound absorption of small-scale 3D printed acoustic metamaterials based on Helmholtz resonators
2018
Acoustic metamaterials have recently become of interest for their ability to attenuate sound by breaking the mass-density law. In this paper, acoustic metamaterials based on Helmholtz resonators and capable of attenuating sound up to 30 dB are fabricated for sound absorption applications in the small scale. The proposed metamaterials are subwavelength at a factor of $\lambda /12$ with respect to the lateral dimension of the units. The directional response due to the position of the acoustic source on the sound attenuation provided by the metamaterial is investigated by controlling the location of a loudspeaker with a robot arm. To enhance and broaden the absorption bands, structural modific…
Parametrical Optomechanical Oscillations in PhoXonic Whispering Gallery Mode Resonators
2019
AbstractWe report on the experimental and theoretical analysis of parametrical optomechanical oscillations in hollow spherical phoxonic whispering gallery mode resonators due to radiation pressure. The optically excited acoustic eigenmodes of the phoxonic cavity oscillate regeneratively leading to parametric oscillation instabilities.
Discrete Time Versus Continuous Time Approach to the Autoimmune Response
1989
A discrete time model for the immune regulation recently proposed by Weisbuch and Atlan is extended to continuous coupling coefficients as well as to continuous concentration rates in continuous time. It is shown that depending on the choice of the network parameters typical immune responses can be observed.
A Novel Technique for Deembeding the Unloaded Resonance Frequency from Measurements of Microwave Cavities
2006
[EN] A novel technique to extract the influence of coupling networks on the resonant frequency of cavities in one-port measurements is presented. The determination of the unloaded resonant frequency is performed directly from measurements without either the need to obtain the electromagnetic fields in the resonator or to deembed the delay of transmission lines from the measuring equipment to the resonator. The importance of the Foster's form on the modeling of the frequency detuning of the resonators is also discussed and a criterion for the choice of the appropriate Foster's form is suggested. The procedure is validated with simulations and experimental measurements of manufactured cavities
A new empirical method for extracting unloaded resonant frequencies from microwave resonant cavities
2003
Equivalent circuits traditionally used to model resonators and coupling networks in the vicinity of a resonance provide values of unloaded resonant frequencies which usually do not agree with experimental results. A new empirical method for the extraction of influence of coupling networks on resonant cavities is presented. The characterization of coupling structures is performed directly from measurements without the need of obtaining the electromagnetic fields inside the cavity, which is very interesting from a practical point of view. Results are validated with simulations and experimental measurements. The accuracy of some cavity applications, such as dielectric characterization techniqu…
Mode cleaning in graphene oxide-doped polymeric whispering gallery mode microresonators
2020
The strategy to incorporate graphene oxide (GO) in a composite material offers significant opportunities to realize compact photonic devices, such as saturable absorbers and polarization selective devices. However, the processing of GO-based composites by direct laser writing, which would afford vast patterning and material flexibility in a single step process, has been little addressed. In this work, we investigated the mechanisms underlying a mode cleaning effect in polymeric whispering gallery mode microresonators containing GO, aiming at the development of on-chip integrable photonic devices. We fabricated the microresonators (cavity loaded Q-factor of 20 000 at 1550 nm) in a single ste…
Development of ultra-fast thulium-doped fiber lasers - Prospects for 2μm-nanophotonics.
2021
Developing highly coherent pulsed sources around the 2 µm wavelengthhas been a particularly dynamic field of research in the last couples of years,due to its numerous applications. In optical telecommunication, the wavelength rangearound 2 µm is one of the most promising solutions to increase the transmission capacitypast the current technological bottleneck. In this context, passively mode-lockedfiber lasers appear as a high potential solution for cheap laser sources, due to their veryhigh coherence and intrinsic compatibility with telecommunication systems.Passively mode-locked fiber lasers at 1,55 µm and their ultrafast dynamics is oneof the specialty of the ICB laboratory, and the aim i…
Ultrahigh-Q Tunable Whispering-Gallery-Mode Microresonator
2009
Typical microresonators exhibit a large frequency spacing between resonances and a limited tunability. This impedes their use in a large class of applications which require a resonance of the microcavity to coincide with a predetermined frequency. Here, we experimentally overcome this limitation with highly prolate-shaped whispering-gallery-mode "bottle microresonators" fabricated from standard optical glass fibers. Our resonators combine an ultra-high quality factor of 360 million, a small mode volume, and near lossless fibre coupling, characteristic of whispering-gallery-mode resonators, with a simple and customizable mode structure enabling full tunability.