Dark state in a nonlinear optomechanical system with quadratic coupling
NASA Astrophysics Data System (ADS)
Huang, Yue-Xin; Zhou, Xiang-Fa; Guo, Guang-Can; Zhang, Yong-Sheng
We consider a hybrid system consisting of a cavity optomechanical device with nonlinear quadratic radiation pressure coupled to an atomic ensemble. By considering the collective excitation, we show that this system supports nontrivial, nonlinear dark states. The coupling strength can be tuned via the lasers that ensure the population transfer adiabatically between the mechanical modes and the collective atomic excitations in a controlled way. In addition, we show how to detect the dark-state resonance by calculating the single-photon spectrum of the output fields and the transmission of the probe beam based on two-phonon optomechanically induced transparency. Possible application and extension of the dark states are also discussed. Supported by the National Fundamental Research Program of China (Grants No. 2011CB921200 and No. 2011CBA00200), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB01030200), and NSFC (Grants No. 61275122 and 11474266).
Nonlinear optomechanics with graphene
NASA Astrophysics Data System (ADS)
Shaffer, Airlia; Patil, Yogesh Sharad; Cheung, Hil F. H.; Wang, Ke; Vengalattore, Mukund
2016-05-01
To date, studies of cavity optomechanics have been limited to exploiting the linear interactions between the light and mechanics. However, investigations of quantum signal transduction, quantum enhanced metrology and manybody physics with optomechanics each require strong, nonlinear interactions. Graphene nanomembranes are an exciting prospect for realizing such studies due to their inherently nonlinear nature and low mass. We fabricate large graphene nanomembranes and study their mechanical and optical properties. By using dark ground imaging techniques, we correlate their eigenmode shapes with the measured dissipation. We study their hysteretic response present even at low driving amplitudes, and their nonlinear dissipation. Finally, we discuss ongoing efforts to use these resonators for studies of quantum optomechanics and force sensing. This work is supported by the DARPA QuASAR program through a Grant from the ARO.
Ramos, Daniel Frank, Ian W.; Deotare, Parag B.; Bulu, Irfan; Lončar, Marko
2014-11-03
We investigate the coupling between mechanical and optical modes supported by coupled, freestanding, photonic crystal nanobeam cavities. We show that localized cavity modes for a given gap between the nanobeams provide weak optomechanical coupling with out-of-plane mechanical modes. However, we show that the coupling can be significantly increased, more than an order of magnitude for the symmetric mechanical mode, due to optical resonances that arise from the interaction of the localized cavity modes with standing waves formed by the reflection from thesubstrate. Finally, amplification of motion for the symmetric mode has been observed and attributed to the strong optomechanical interaction of our hybrid system. The amplitude of these self-sustained oscillations is large enough to put the system into a non-linear oscillation regime where a mixing between the mechanical modes is experimentally observed and theoretically explained.
Quantum-criticality-induced strong Kerr nonlinearities in optomechanical systems
Lü, Xin-You; Zhang, Wei-Min; Ashhab, Sahel; Wu, Ying; Nori, Franco
2013-01-01
We investigate a hybrid electro-optomechanical system that allows us to realize controllable strong Kerr nonlinearities even in the weak-coupling regime. We show that when the controllable electromechanical subsystem is close to its quantum critical point, strong photon-photon interactions can be generated by adjusting the intensity (or frequency) of the microwave driving field. Nonlinear optical phenomena, such as the appearance of the photon blockade and the generation of nonclassical states (e.g., Schrödinger cat states), are demonstrated in the weak-coupling regime, making the observation of strong Kerr nonlinearities feasible with currently available optomechanical technology. PMID:24126279
Enhanced nonlinear interactions in quantum optomechanics via mechanical amplification
NASA Astrophysics Data System (ADS)
Lemonde, Marc-Antoine; Didier, Nicolas; Clerk, Aashish A.
2016-04-01
The quantum nonlinear regime of optomechanics is reached when nonlinear effects of the radiation pressure interaction are observed at the single-photon level. This requires couplings larger than the mechanical frequency and cavity-damping rate, and is difficult to achieve experimentally. Here we show how to exponentially enhance the single-photon optomechanical coupling strength using only additional linear resources. Our method is based on using a large-amplitude, strongly detuned mechanical parametric drive to amplify mechanical zero-point fluctuations and hence enhance the radiation pressure interaction. It has the further benefit of allowing time-dependent control, enabling pulsed schemes. For a two-cavity optomechanical set-up, we show that our scheme generates photon blockade for experimentally accessible parameters, and even makes the production of photonic states with negative Wigner functions possible. We discuss how our method is an example of a more general strategy for enhancing boson-mediated two-particle interactions and nonlinearities.
Sensitivity of optical mass sensor enhanced by optomechanical coupling
He, Yong
2015-03-23
Optical mass sensors based on cavity optomechanics employ radiation pressure force to drive mechanical resonator whose mechanical susceptibility can be described by nonlinear optical transmission spectrum. In this paper, we present an optical mass sensor based on a two-cavity optomechanical system where the mechanical damping rate can be decreased by adjusting a pump power so that the mass sensitivity which depends on the mechanical quality factor has been enhanced greatly. Compared with that of an optical mass sensor based on single-cavity optomechanics, the mass sensitivity of the optical mass sensor is improved by three orders of magnitude. This is an approach to enhance the mass sensitivity by means of optomechanical coupling, which is suitable for all mass sensor based on cavity optomechanics. Finally, we illustrate the accurate measurement for the mass of a few chromosomes, which can be achieved based on the current experimental conditions.
Enhanced nonlinear interactions in quantum optomechanics via mechanical amplification
Lemonde, Marc-Antoine; Didier, Nicolas; Clerk, Aashish A.
2016-01-01
The quantum nonlinear regime of optomechanics is reached when nonlinear effects of the radiation pressure interaction are observed at the single-photon level. This requires couplings larger than the mechanical frequency and cavity-damping rate, and is difficult to achieve experimentally. Here we show how to exponentially enhance the single-photon optomechanical coupling strength using only additional linear resources. Our method is based on using a large-amplitude, strongly detuned mechanical parametric drive to amplify mechanical zero-point fluctuations and hence enhance the radiation pressure interaction. It has the further benefit of allowing time-dependent control, enabling pulsed schemes. For a two-cavity optomechanical set-up, we show that our scheme generates photon blockade for experimentally accessible parameters, and even makes the production of photonic states with negative Wigner functions possible. We discuss how our method is an example of a more general strategy for enhancing boson-mediated two-particle interactions and nonlinearities. PMID:27108814
Nonlinear optomechanical measurement of mechanical motion.
Brawley, G A; Vanner, M R; Larsen, P E; Schmid, S; Boisen, A; Bowen, W P
2016-01-01
Precision measurement of nonlinear observables is an important goal in all facets of quantum optics. This allows measurement-based non-classical state preparation, which has been applied to great success in various physical systems, and provides a route for quantum information processing with otherwise linear interactions. In cavity optomechanics much progress has been made using linear interactions and measurement, but observation of nonlinear mechanical degrees-of-freedom remains outstanding. Here we report the observation of displacement-squared thermal motion of a micro-mechanical resonator by exploiting the intrinsic nonlinearity of the radiation-pressure interaction. Using this measurement we generate bimodal mechanical states of motion with separations and feature sizes well below 100 pm. Future improvements to this approach will allow the preparation of quantum superposition states, which can be used to experimentally explore collapse models of the wavefunction and the potential for mechanical-resonator-based quantum information and metrology applications. PMID:26996234
Nonlinear optomechanical measurement of mechanical motion
Brawley, G. A.; Vanner, M. R.; Larsen, P. E.; Schmid, S.; Boisen, A.; Bowen, W. P.
2016-01-01
Precision measurement of nonlinear observables is an important goal in all facets of quantum optics. This allows measurement-based non-classical state preparation, which has been applied to great success in various physical systems, and provides a route for quantum information processing with otherwise linear interactions. In cavity optomechanics much progress has been made using linear interactions and measurement, but observation of nonlinear mechanical degrees-of-freedom remains outstanding. Here we report the observation of displacement-squared thermal motion of a micro-mechanical resonator by exploiting the intrinsic nonlinearity of the radiation-pressure interaction. Using this measurement we generate bimodal mechanical states of motion with separations and feature sizes well below 100 pm. Future improvements to this approach will allow the preparation of quantum superposition states, which can be used to experimentally explore collapse models of the wavefunction and the potential for mechanical-resonator-based quantum information and metrology applications. PMID:26996234
The nonclassical effects in coupled optomechanical array
NASA Astrophysics Data System (ADS)
Zhou, Wenjun; Cheng, Jiong; Zhang, Wenzhao; Yousif, Taha; Zhou, Ling
2015-07-01
We investigate a coupled array of ? identical cavity optomechanical systems. By adiabatically eliminating the cavity fields, we derive an effective Hamiltonian of the ? phonon modes coupled via XX form. We show further that the coupled mechanical oscillators can be used to transmit state and the single mode of the oscillator and the two-mode of neighbor oscillators can exhibit squeezing simultaneously. Under the suitable regime of parameters, the phonon blockade is exhibited.
Strong Optomechanical Coupling in Nanobeam Cavities based on Hetero Optomechanical Crystals
Huang, Zhilei; Cui, Kaiyu; Li, Yongzhuo; Feng, Xue; Liu, Fang; Zhang, Wei; Huang, Yidong
2015-01-01
Nanobeam cavities based on hetero optomechanical crystals are proposed. With optical and mechanical modes separately confined by two types of periodic structures, the mechanical frequency is designed as high as 5.88 GHz. Due to the optical field and the strain field concentrated in the optomechanical cavity and resembling each other with an enhanced overlap, a high optomechanical coupling rate of 1.31 MHz is predicted. PMID:26530128
Linear and nonlinear optomechanics in a cryogenic membrane-in-the-middle system
NASA Astrophysics Data System (ADS)
Lee, Donghun; Underwood, Mitchell; Mason, David; Shkarin, Alexey; Hoch, Scott; Harris, Jack
2014-03-01
In cavity optomechanics, linear optomechanical interactions have been used to readout and cool the motion of mechanical oscillators, while nonlinear interactions have been proposed to study quantum non-demolition measurements of mechanical oscillators and the production of non-Gaussian mechanical states. A membrane-in-the-middle system can provide both types of interactions. In this talk, we will present recent results measured in both linear and nonlinear interaction regimes with a membrane-in-the-middle system operating at 500 mK. Linear coupling in this device enables us to cool the mechanical mode of a SiN membrane at 705 kHz to roughly one phonon. During the cooling measurement, we also observed strong asymmetry between the mechanical sidebands, in agreement with the phonon number inferred from other measurements. We also measured nonlinear optomechanics, in particular the quadratic interaction. With a simple theoretical model, we systematically characterized the classical dynamics arising from this quadratic optomechanical interaction. We expect that by combining quadratic coupling with resolved-sideband laser cooling, this device will be able to explore the aforementioned quantum phenomena. We gracefully acknowledge financial support from AFOSR (No. FA9550-90-1-0484).
Optomechanical Enhancement of Doubly Resonant 2D Optical Nonlinearity.
Yi, Fei; Ren, Mingliang; Reed, Jason C; Zhu, Hai; Hou, Jiechang; Naylor, Carl H; Johnson, A T Charlie; Agarwal, Ritesh; Cubukcu, Ertugrul
2016-03-01
Emerging two-dimensional semiconductor materials possess a giant second order nonlinear response due to excitonic effects while the monolayer thickness of such active materials limits their use in practical nonlinear devices. Here, we report 3300 times optomechanical enhancement of second harmonic generation from a MoS2 monolayer in a doubly resonant on-chip optical cavity. We achieve this by engineering the nonlinear light-matter interaction in a microelectro-mechanical system enabled optical frequency doubling device based on an electrostatically tunable Fabry-Perot microresonator. Our versatile optomechanical approach will pave the way for next generation efficient on-chip tunable light sources, sensors, and systems based on molecularly thin materials. PMID:26854706
NASA Astrophysics Data System (ADS)
Bai, C.; Hou, B. P.; Lai, D. G.; Wu, D.
2016-04-01
We consider the optomechanically induced transparency in the double quadratically coupled optomechanical cavities within a common reservoir, in which the two cavities are driven by the coupling fields. It is shown that the probe transparency is improved by increasing the coupling field (the left coupling field) applied on the probing cavity, but the transparency position (the probe frequency of the maximal transparency) is shifted to high frequency. The coupling field (the right coupling field) applied on the other quadratically coupled cavity can lead to a low-frequency shift for the transparency position, which can be used to fix the transparency position by adjusting the right coupling field. We get the quantitative findings that the transparency position is exactly determined by the intensity difference between the two coupling fields. On the other hand, it is found that when the two coupled optomechanical cavities interact with their common reservoir, the cross decay induced by the common reservoir can improve the probe transparency and widen the transparency window. Finally, the effects of the environment's temperature on the transparency are investigated. This will be useful in cooling the membrane, squeezing and entangling the output fields.
NASA Astrophysics Data System (ADS)
Liu, Jingyi; Zhang, Wenzhao; Li, Xun; Yan, Weibin; Zhou, Ling
2016-06-01
We investigate the two-photon transport properties inside one-dimensional waveguide side coupled to an atom-optomechanical system, aiming to control the two-photon transport by using the nonlinearity. By generalizing the scheme of Phys. Rev. A 90, 033832, we show that Kerr nonlinearity induced by the four-level atoms is remarkable and can make the photons antibunching, while the nonlinear interaction of optomechanical coupling participates in both the single photon and the two photon processes so that it can make the two photons exhibiting bunching and antibunching.
Duality and bistability in an optomechanical cavity coupled to a Rydberg superatom
NASA Astrophysics Data System (ADS)
Yan, Dong; Wang, Zhi-Hai; Ren, Chun-Nian; Gao, Hang; Li, Yong; Wu, Jin-Hui
2015-02-01
We study the steady-state behaviors of a typical optomechanical cavity coupled to cold Rydberg atoms with dipole-dipole interactions. The interacting atoms are described as one superatom of three collective states in a ladder configuration in the limit of a strong dipole blockade and a weak cavity field. We find that this hybrid system exhibits phenomena of conditional duality and nonlinear bistability in terms of mirror displacement, number of cavity photons, and Rydberg population, depending on the detuning of the cavity field, the strength of the optical driving field, and the number of cold atoms. It is of particular interest that the two branches of relevant curves may intersect to yield a nontrivial duality and bistability. Such correlated optical, mechanical, and atomic responses arise from the efficient feedback between atom-light and optomechanical interactions and have realistic applications, e.g., in realizing accurate optomechanical detection or attaining deterministic single photons.
Observation of generalized optomechanical coupling and cooling on cavity resonance.
Sawadsky, Andreas; Kaufer, Henning; Nia, Ramon Moghadas; Tarabrin, Sergey P; Khalili, Farid Ya; Hammerer, Klemens; Schnabel, Roman
2015-01-30
Optomechanical coupling between a light field and the motion of a cavity mirror via radiation pressure plays an important role for the exploration of macroscopic quantum physics and for the detection of gravitational waves (GWs). It has been used to cool mechanical oscillators into their quantum ground states and has been considered to boost the sensitivity of GW detectors, e.g., via the optical spring effect. Here, we present the experimental characterization of generalized, that is, dispersive and dissipative, optomechanical coupling, with a macroscopic (1.5 mm)2-size silicon nitride membrane in a cavity-enhanced Michelson-type interferometer. We report for the first time strong optomechanical cooling based on dissipative coupling, even on cavity resonance, in excellent agreement with theory. Our result will allow for new experimental regimes in macroscopic quantum physics and GW detection. PMID:25679890
Cavity mode frequencies and strong optomechanical coupling in two-membrane cavity optomechanics
NASA Astrophysics Data System (ADS)
Li, Jie; Xuereb, André; Malossi, Nicola; Vitali, David
2016-08-01
We study the cavity mode frequencies of a Fabry–Pérot cavity containing two vibrating dielectric membranes. We derive the equations for the mode resonances and provide approximate analytical solutions for them as a function of the membrane positions, which act as an excellent approximation when the relative and center-of-mass position of the two membranes are much smaller than the cavity length. With these analytical solutions, one finds that extremely large optomechanical coupling of the membrane relative motion can be achieved in the limit of highly reflective membranes when the two membranes are placed very close to a resonance of the inner cavity formed by them. We also study the cavity finesse of the system and verify that, under the conditions of large coupling, it is not appreciably affected by the presence of the two membranes. The achievable large values of the ratio between the optomechanical coupling and the cavity decay rate, g/κ , make this two-membrane system the simplest promising platform for implementing cavity optomechanics in the strong coupling regime.
Integrated III-V Photonic Crystal - Si waveguide platform with tailored optomechanical coupling
NASA Astrophysics Data System (ADS)
Tsvirkun, Viktor; Surrente, Alessandro; Raineri, Fabrice; Beaudoin, Grégoire; Raj, Rama; Sagnes, Isabelle; Robert-Philip, Isabelle; Braive, Rémy
2015-11-01
Optomechanical systems, in which the vibrations of a mechanical resonator are coupled to an electromagnetic radiation, have permitted the investigation of a wealth of novel physical effects. To fully exploit these phenomena in realistic circuits and to achieve different functionalities on a single chip, the integration of optomechanical resonators is mandatory. Here, we propose a novel approach to heterogeneously integrate arrays of two-dimensional photonic crystal defect cavities on top of silicon-on-insulator waveguides. The optomechanical response of these devices is investigated and evidences an optomechanical coupling involving both dispersive and dissipative mechanisms. By controlling the optical coupling between the waveguide and the photonic crystal, we were able to vary and understand the relative strength of these couplings. This scalable platform allows for an unprecedented control on the optomechanical coupling mechanisms, with a potential benefit in cooling experiments, and for the development of multi-element optomechanical circuits in the framework of optomechanically-driven signal-processing applications.
Fast cooling in dispersively and dissipatively coupled optomechanics.
Chen, Tian; Wang, Xiang-Bin
2015-01-01
The cooling performance of an optomechanical system comprising both dispersive and dissipative coupling is studied. Here, we present a scheme to cool a mechanical resonator to its ground state in finite time using a chirped pulse. We show that there is distinct advantage in using the chirp-pulse scheme to cool a resonator rapidly. The cooling behaviors of dispersively and dissipatively coupled system is also explored with different types of incident pulses and different coupling strengths. Our scheme is feasible in cooling the resonator for a wide range of the parameter region. PMID:25582660
Quantum Coherence of Optomechanical Systems in the Single-photon Strong Coupling Regime
NASA Astrophysics Data System (ADS)
Hu, Dan; Huang, Shang-Yu; Liao, Jie-Qiao; Tian, Lin; Goan, Hsi-Sheng
2015-03-01
Optomechanical systems with ultrastrong coupling could demonstrate nonlinear optical effects such as photon blockade. The system-bath couplings in these systems play an essential role in observing these effects. In this work, we use a dressed-state master equation approach to study the quantum coherence of an optomechanical system. In this approach, the system-bath couplings are decomposed in terms of the eigenbasis of the optomechanical system, where the mechanical state is displaced by finite photon occupation. Compared with the standard master equation often seen in the literature, our master equation includes photon-number-dependent terms that induce dephasing. We calculate cavity dephasing, second-order photon correlation, and two-cavity entanglement using the dressed-state master equation. At high temperature, our master equation predicts faster decay of the quantum coherence than with the standard master equation. The second-order photon correlation derived with our master equation shows less antibunching than that with the standard master equation. This work is supported by awards from DARPA, NSF, JSPS (Japan), MOST (Taiwan) and NTU (Taiwan).
Squeezed light and correlated photons from dissipatively coupled optomechanical systems
NASA Astrophysics Data System (ADS)
Kilda, Dainius; Nunnenkamp, Andreas
2016-01-01
We study theoretically the squeezing spectrum and second-order correlation function of the output light for an optomechanical system in which a mechanical oscillator modulates the cavity linewidth (dissipative coupling). We find strong squeezing coinciding with the normal-mode frequencies of the linearized system. In contrast to dispersive coupling, squeezing is possible in the resolved-sideband limit simultaneously with sideband cooling. The second-order correlation function shows damped oscillations, whose properties are given by the mechanical-like, the optical-like normal mode, or both, and can be below shot-noise level at finite times, {g}(2)(τ )\\lt 1.
Entanglement of Coupled Optomechanical Systems Improved by Optical Parametric Amplifiers
NASA Astrophysics Data System (ADS)
Pan, Guixia; Xiao, Ruijie; Zhou, Ling
2016-04-01
A scheme to generate the stationary entanglement of two distant coupled optical cavities placed optical parametric amplifiers is proposed. We study how the optical parametric amplifiers can affect the entanglement behaviors of the movable mirrors and the cavity fields. With the existence of optical parametric amplifiers, we show that larger stationary entanglement of optical and mechanical modes can be obtained and the entanglement increases with the increasing parametric gain. Especially, the degree of entanglement between the two cavity fields is more pronouncedly enhanced. Moreover, for a fixed parametric gain, the entanglement of distant cavity optomechanical systems increases as the input laser power is increased.
Entanglement of Coupled Optomechanical Systems Improved by Optical Parametric Amplifiers
NASA Astrophysics Data System (ADS)
Pan, Guixia; Xiao, Ruijie; Zhou, Ling
2016-08-01
A scheme to generate the stationary entanglement of two distant coupled optical cavities placed optical parametric amplifiers is proposed. We study how the optical parametric amplifiers can affect the entanglement behaviors of the movable mirrors and the cavity fields. With the existence of optical parametric amplifiers, we show that larger stationary entanglement of optical and mechanical modes can be obtained and the entanglement increases with the increasing parametric gain. Especially, the degree of entanglement between the two cavity fields is more pronouncedly enhanced. Moreover, for a fixed parametric gain, the entanglement of distant cavity optomechanical systems increases as the input laser power is increased.
Cavity Optomechanics: Coherent Coupling of Light and Mechanical Oscillators
NASA Astrophysics Data System (ADS)
Kippenberg, Tobias J.
2012-06-01
The mutual coupling of optical and mechanical degrees of freedom via radiation pressure has been a subject of interest in the context of quantum limited displacements measurements for Gravity Wave Detection for many decades, however light forces have remained experimentally unexplored in such systems. Recent advances in nano- and micro-mechanical oscillators have for the first time allowed the observation of radiation pressure phenomena in an experimental setting and constitute the expanding research field of cavity optomechanics [1]. These advances have allowed achieving to enter the quantum regime of mechanical systems, which are now becoming a third quantum technology after atoms, ions and molecules in a first and electronic circuits in a second wave. In this talk I will review these advances. Using on-chip micro-cavities that combine both optical and mechanical degrees of freedom in one and the same device [2], radiation pressure back-action of photons is shown to lead to effective cooling [3-6]) of the mechanical oscillator mode using dynamical backaction, which has been predicted by Braginsky as early as 1969 [4]. This back-action cooling exhibits many close analogies to atomic laser cooling. With this novel technique the quantum mechanical ground state of a micromechanical oscillator has been prepared with high probability using both microwave and optical fields. In our research this is reached using cryogenic precooling to ca. 800 mK in conjunction with laser cooling, allowing cooling of micromechanical oscillator to only motional 1.7 quanta, implying that the mechanical oscillator spends about 40% of its time in the quantum ground state. Moreover it is possible in this regime to observe quantum coherent coupling in which the mechanical and optical mode hybridize and the coupling rate exceeds the mechanical and optical decoherence rate [7]. This accomplishment enables a range of quantum optical experiments, including state transfer from light to mechanics
Integrated III-V Photonic Crystal--Si waveguide platform with tailored optomechanical coupling.
Tsvirkun, Viktor; Surrente, Alessandro; Raineri, Fabrice; Beaudoin, Grégoire; Raj, Rama; Sagnes, Isabelle; Robert-Philip, Isabelle; Braive, Rémy
2015-01-01
Optomechanical systems, in which the vibrations of a mechanical resonator are coupled to an electromagnetic radiation, have permitted the investigation of a wealth of novel physical effects. To fully exploit these phenomena in realistic circuits and to achieve different functionalities on a single chip, the integration of optomechanical resonators is mandatory. Here, we propose a novel approach to heterogeneously integrate arrays of two-dimensional photonic crystal defect cavities on top of silicon-on-insulator waveguides. The optomechanical response of these devices is investigated and evidences an optomechanical coupling involving both dispersive and dissipative mechanisms. By controlling the optical coupling between the waveguide and the photonic crystal, we were able to vary and understand the relative strength of these couplings. This scalable platform allows for an unprecedented control on the optomechanical coupling mechanisms, with a potential benefit in cooling experiments, and for the development of multi-element optomechanical circuits in the framework of optomechanically-driven signal-processing applications. PMID:26567535
Integrated III-V Photonic Crystal – Si waveguide platform with tailored optomechanical coupling
Tsvirkun, Viktor; Surrente, Alessandro; Raineri, Fabrice; Beaudoin, Grégoire; Raj, Rama; Sagnes, Isabelle; Robert-Philip, Isabelle; Braive, Rémy
2015-01-01
Optomechanical systems, in which the vibrations of a mechanical resonator are coupled to an electromagnetic radiation, have permitted the investigation of a wealth of novel physical effects. To fully exploit these phenomena in realistic circuits and to achieve different functionalities on a single chip, the integration of optomechanical resonators is mandatory. Here, we propose a novel approach to heterogeneously integrate arrays of two-dimensional photonic crystal defect cavities on top of silicon-on-insulator waveguides. The optomechanical response of these devices is investigated and evidences an optomechanical coupling involving both dispersive and dissipative mechanisms. By controlling the optical coupling between the waveguide and the photonic crystal, we were able to vary and understand the relative strength of these couplings. This scalable platform allows for an unprecedented control on the optomechanical coupling mechanisms, with a potential benefit in cooling experiments, and for the development of multi-element optomechanical circuits in the framework of optomechanically-driven signal-processing applications. PMID:26567535
NASA Astrophysics Data System (ADS)
Krause, Alexander Grey
Light has long been used for the precise measurement of moving bodies, but the burgeoning field of optomechanics is concerned with the interaction of light and matter in a regime where the typically weak radiation pressure force of light is able to push back on the moving object. This field began with the realization in the late 1960's that the momentum imparted by a recoiling photon on a mirror would place fundamental limits on the smallest measurable displacement of that mirror. This coupling between the frequency of light and the motion of a mechanical object does much more than simply add noise, however. It has been used to cool objects to their quantum ground state, demonstrate electromagnetically-induced-transparency, and modify the damping and spring constant of the resonator. Amazingly, these radiation pressure effects have now been demonstrated in systems ranging 18 orders of magnitude in mass (kg to fg). In this work we will focus on three diverse experiments in three different optomechanical devices which span the fields of inertial sensors, closed-loop feedback, and nonlinear dynamics. The mechanical elements presented cover 6 orders of magnitude in mass (ng to fg), but they all employ nano-scale photonic crystals to trap light and resonantly enhance the light-matter interaction. In the first experiment we take advantage of the sub-femtometer displacement resolution of our photonic crystals to demonstrate a sensitive chip-scale optical accelerometer with a kHz-frequency mechanical resonator. This sensor has a noise density of approximately 10 micro-g/rt-Hz over a useable bandwidth of approximately 20 kHz and we demonstrate at least 50 dB of linear dynamic sensor range. We also discuss methods to further improve performance of this device by a factor of 10. In the second experiment, we used a closed-loop measurement and feedback system to damp and cool a room-temperature MHz-frequency mechanical oscillator from a phonon occupation of 6.5 million down to
Controllable optomechanical coupling in serially-coupled triple resonators
Huang, Chenguang Zhao, Yunsong; Fan, Jiahua; Zhu, Lin
2014-12-15
Radiation pressure can efficiently couple mechanical modes with optical modes in an optical cavity. The coupling efficiency is quite dependent on the interaction between the optical mode and mechanical mode. In this report, we investigate a serially-coupled triple resonator system, where a freestanding beam is placed in the vicinity of the middle resonator. In this coupled system, we demonstrate that the mechanical mode of the free-standing beam can be selectively coupled to different resonance supermodes through the near field interaction.
Slot-mode optomechanical crystals with enhanced coupling and multimode functionality
NASA Astrophysics Data System (ADS)
Grutter, Karen; Davanco, Marcelo; Srinivasan, Kartik
A number of cavity optomechanics applications involve multiple interacting optical and mechanical modes. A key challenge in such systems is developing multimode platforms with both flexibility in the optical and mechanical designs and interactions as strong as those shown in single-mode systems. We thus present slot-mode optomechanical crystals, in which photonic and phononic crystal nanobeams separated by a narrow slot couple optomechanically. We pattern these beams to confine a low-loss optical mode in the slot and a mechanical breathing mode at the center of the mechanical beam. This structure has large optomechanical coupling rates and great design flexibility toward multimode systems. We demonstrate this in Si3N4 slot-mode devices, with 980 nm optical modes coupling to mechanical modes at 3.4 GHz, 1.8 GHz, and 400 MHz. We use Si3N4 tensile stress to shrink slot widths to 24 nm, greatly enhancing optomechanical coupling. Finally, with this platform, we develop multimode systems with three-beam geometries, in which two different mechanical modes couple to one optical mode and two different optical modes couple to one mechanical mode. The authors acknowledge funding from DARPA (MESO) and the National Research Council Research Associateship Program.
Jusserand, B; Poddubny, A N; Poshakinskiy, A V; Fainstein, A; Lemaitre, A
2015-12-31
Polariton-mediated light-sound interaction is investigated through resonant Brillouin scattering experiments in GaAs/AlAs multiple-quantum wells. Photoelastic coupling enhancement at exciton-polariton resonance reaches 10(5) at 30 K as compared to a typical bulk solid room temperature transparency value. When applied to GaAs based cavity optomechanical nanodevices, this result opens the path to huge displacement sensitivities and to ultrastrong coupling regimes in cavity optomechanics with couplings g(0) in the range of 100 GHz. PMID:26765028
Effects of squeezed-film damping on the optomechanical nonlinearity in dual-nanoweb fiber
NASA Astrophysics Data System (ADS)
Koehler, J. R.; Butsch, A.; Euser, T. G.; Noskov, R. E.; St. J. Russell, P.
2013-11-01
The freely-suspended glass membranes in a dual-nanoweb fiber, driven at resonance by intensity-modulated light, exhibit a giant optomechanical nonlinearity. We experimentally investigate the effect of squeezed-film damping by exploring the pressure dependence of resonant frequency and mechanical quality factor. As a consequence of the unusually narrow slot between the nanowebs (22 μm by 550 nm), the gas-spring effect causes a pressure-dependent frequency shift that is ˜15 times greater than typically measured in micro-electro-mechanical devices. When evacuated, the dual-nanoweb fiber yields a quality factor of ˜3 600 and a resonant optomechanical nonlinear coefficient that is ˜60 000 times larger than the Kerr effect.
An opto-mechanical coupled-ring reflector driven by optical force for lasing wavelength control
NASA Astrophysics Data System (ADS)
Ren, M.; Cai, H.; Chin, L. K.; Huang, J. G.; Gu, Y. D.; Radhakrishnan, K.; Ser, W.; Liu, A. Q.
2016-02-01
In this paper, an opto-mechanical coupled-ring reflector driven by optical gradient force is applied in an external-cavity tunable laser. A pair of mutually coupled ring resonators with a free-standing arc serves as a movable reflector. It obtains a 13.3-nm wavelength tuning range based on an opto-mechanical lasing-wavelength tuning coefficient of 127 GHz/nm. The potential applications include optical network, on-chip optical trapping, sensing, and biology detection.
NASA Astrophysics Data System (ADS)
Balram, Krishna C.; Davanço, Marcelo I.; Song, Jin Dong; Srinivasan, Kartik
2016-05-01
Optomechanical cavities have been studied for applications ranging from sensing to quantum information science. Here, we develop a platform for nanoscale cavity optomechanical circuits in which optomechanical cavities supporting co-localized 1,550 nm photons and 2.4 GHz phonons are combined with photonic and phononic waveguides. Working in GaAs facilitates manipulation of the localized mechanical mode either with a radiofrequency field through the piezo-electric effect, which produces acoustic waves that are routed and coupled to the optomechanical cavity by phononic-crystal waveguides, or optically through the strong photoelastic effect. Together with mechanical state preparation and sensitive readout, we use this to demonstrate an acoustic wave interference effect, similar to atomic coherent population trapping, in which radiofrequency-driven coherent mechanical motion is cancelled by optically driven motion. Manipulating cavity optomechanical systems with equal facility through both photonic and phononic channels enables new architectures for signal transduction between the optical, electrical and mechanical domains.
NASA Astrophysics Data System (ADS)
Yousif, Taha; Zhou, Wenjun; Zhou, Ling
2014-08-01
We investigate coupled two-cavity optomechanical systems to show their potential usages by revealing the physical processes. Under two conditions, we deduce the correspondingly effective Hamiltonian with beam splitter type and nondegenerate parametric-down conversion type, respectively. Including the whole interactions, we show that the state transfer and the stationary entanglement between the two mechanical resonators can be achieved.
Cavity optomechanics with a nonlinear photonic-crystal nanomembrane
Makles, Kevin; Kuhn, Aurélien; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine; Antoni, Thomas; Braive, Rémy; Sagnes, Isabelle; Robert-Philip, Isabelle
2014-12-04
We have designed, fabricated and characterized a nanomembrane which could be used as a moving end mirror of a Fabry-Perot cavity. The high reflectivity and optimized mechanical properties of the membrane should allow us to demonstrate the mechanical ground state of the membrane. As any sub-micron mechanical resonator, our system demonstrates nonlinear dynamical effects. We characterize the mechanical response to a strong pump drive and observe a shift in the oscillation frequency and phase conjugation of the mechanical mode. Such nonlinear effects are expected to play a role in the quantum dynamics of the membrane as well.
NASA Astrophysics Data System (ADS)
Jusserand, B.; Poddubny, A. N.; Poshakinskiy, A. V.; Fainstein, A.; Lemaitre, A.
2015-12-01
Polariton-mediated light-sound interaction is investigated through resonant Brillouin scattering experiments in GaAs /AlAs multiple-quantum wells. Photoelastic coupling enhancement at exciton-polariton resonance reaches 105 at 30 K as compared to a typical bulk solid room temperature transparency value. When applied to GaAs based cavity optomechanical nanodevices, this result opens the path to huge displacement sensitivities and to ultrastrong coupling regimes in cavity optomechanics with couplings g0 in the range of 100 GHz.
Solitons in optomechanical arrays.
Gan, Jing-Hui; Xiong, Hao; Si, Liu-Gang; Lü, Xin-You; Wu, Ying
2016-06-15
We show that optical solitons can be obtained with a one-dimensional optomechanical array that consists of a chain of periodically spaced identical optomechanical systems. Unlike conventional optical solitons, which originate from nonlinear polarization, the optical soliton here stems from a new mechanism, namely, phonon-photon interaction. Under proper conditions, the phonon-photon induced nonlinearity that refers to the optomechanical nonlinearity will exactly compensate the dispersion caused by photon hopping of adjacent optomechanical systems. Moreover, the solitons are capable of exhibiting very low group velocity, depending on the photon hopping rate, which may lead to many important applications, including all-optical switches and on-chip optical architecture. This work may extend the range of optomechanics and nonlinear optics and provide a new field to study soliton theory and develop corresponding applications. PMID:27304261
Yang, Weijian; Gerke, Stephen Adair; Ng, Kar Wei; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J
2015-01-01
Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors. PMID:26333804
NASA Astrophysics Data System (ADS)
Yang, Weijian; Adair Gerke, Stephen; Wei Ng, Kar; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J.
2015-09-01
Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors.
Yang, Weijian; Adair Gerke, Stephen; Wei Ng, Kar; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J.
2015-01-01
Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors. PMID:26333804
Hybrid quantum systems with ultracold spins and optomechanics
NASA Astrophysics Data System (ADS)
Shaffer, Airlia; Patil, Yogesh Sharad; Cheung, Hil F. H.; Wang, Ke; Date, Aditya; Schwab, Keith; Meystre, Pierre; Vengalattore, Mukund
2016-05-01
Linear cavity optomechanics has enabled radiation pressure cooling and sensing of mechanical resonators at the quantum limits. However, exciting and unrealized avenues such as generating massive macroscopic nonclassical states, quantum signal transduction, and phonon-based manybody physics each require strong, nonlinear interactions. In our group, we are exploring three approaches to realizing strong optomechanical nonlinearities - i. using atomically thin graphene membranes, ii. coupling optomechanical systems with ultracold atomic spins, and iii. using microtoroidal optomechanical resonators strongly coupled to atoms trapped in their evanescent fields. We describe our progress in each of these efforts and discuss ongoing studies on various aspects of quantum enhanced metrology, nonequilibrium dynamics of open quantum systems and quantum transduction using these novel hybrid quantum systems. This work is supported by the DARPA QuASAR program through a Grant from the ARO.
Solving Nonlinear Coupled Differential Equations
NASA Technical Reports Server (NTRS)
Mitchell, L.; David, J.
1986-01-01
Harmonic balance method developed to obtain approximate steady-state solutions for nonlinear coupled ordinary differential equations. Method usable with transfer matrices commonly used to analyze shaft systems. Solution to nonlinear equation, with periodic forcing function represented as sum of series similar to Fourier series but with form of terms suggested by equation itself.
Optomechanical coupling in phoxonic-plasmonic slab cavities with periodic metal strips
NASA Astrophysics Data System (ADS)
Lin, Tzy-Rong; Huang, Yin-Chen; Hsu, Jin-Chen
2015-05-01
We theoretically investigate the optomechanical (OM) coupling of submicron cavities formed in one-dimensional phoxonic-plasmonic slabs. The phoxonic-plasmonic slabs are structured by depositing periodic Ag strips onto the top surfaces of dielectric GaAs slabs to produce dual band gaps for both electromagnetic and acoustic waves, thereby inducing the coupling of surface plasmons with photons for tailoring the OM coupling. We quantify the OM coupling by calculating the temporal modulation of the optical resonance wavelength with the acoustic phonon-induced photoelastic (PE) and moving-boundary (MB) effects. We also consider the appearance of a uniform Ag layer on the bottom surface of the slabs to modulate the photonic-plasmonic coupling. The results show that the PE and MB effects can be constructive or destructive in the overall OM coupling, and their magnitudes depend not only on the quality factors of the resonant modes but also on the mode area, mode overlap, and individual symmetries of the photonic-phononic mode pairs. Lowering the mode area could be effective for enhancing the OM coupling of subwavelength photons and phonons. This study introduces possible engineering applications to achieve enhanced interaction between photons and phonons in nanoscale OM devices.
Optomechanical coupling in phoxonic–plasmonic slab cavities with periodic metal strips
Lin, Tzy-Rong; Huang, Yin-Chen; Hsu, Jin-Chen
2015-05-07
We theoretically investigate the optomechanical (OM) coupling of submicron cavities formed in one-dimensional phoxonic–plasmonic slabs. The phoxonic–plasmonic slabs are structured by depositing periodic Ag strips onto the top surfaces of dielectric GaAs slabs to produce dual band gaps for both electromagnetic and acoustic waves, thereby inducing the coupling of surface plasmons with photons for tailoring the OM coupling. We quantify the OM coupling by calculating the temporal modulation of the optical resonance wavelength with the acoustic phonon-induced photoelastic (PE) and moving-boundary (MB) effects. We also consider the appearance of a uniform Ag layer on the bottom surface of the slabs to modulate the photonic–plasmonic coupling. The results show that the PE and MB effects can be constructive or destructive in the overall OM coupling, and their magnitudes depend not only on the quality factors of the resonant modes but also on the mode area, mode overlap, and individual symmetries of the photonic–phononic mode pairs. Lowering the mode area could be effective for enhancing the OM coupling of subwavelength photons and phonons. This study introduces possible engineering applications to achieve enhanced interaction between photons and phonons in nanoscale OM devices.
NASA Astrophysics Data System (ADS)
Zhang, Yu-Xiang; Wu, Shengjun; Chen, Zeng-Bing; Shikano, Yutaka
2016-08-01
In the optomechanical cooling of a dispersively coupled oscillator, it is only possible to reach the oscillator ground state in the resolved sideband regime, where the cavity-mode linewidth is smaller than the resonant frequency of the mechanical oscillator being cooled. In this paper, we show that the dispersively coupled system can be cooled to the ground state in the unresolved sideband regime using an ancillary oscillator, which has a high quality factor and is coupled to the same optical mode via dissipative interaction. The ancillary oscillator has a resonant frequency close to that of the target oscillator; thus, the ancillary oscillator is also in the unresolved sideband regime. We require only a single blue-detuned laser mode to drive the cavity.
NASA Astrophysics Data System (ADS)
Schneider, Katharina; Seidler, Paul
2016-06-01
We describe the design, fabrication, and characterization of a one-dimensional silicon photonic crystal cavity in which a central slot is used to enhance the overlap between highly localized optical and mechanical modes. The optical mode has an extremely small mode volume of 0.017 $(\\lambda_{vac}/n)^3$, and an optomechanical vacuum coupling rate of 310 kHz is measured. With optical quality factors up to $1.2 \\cdot 10^5$, fabricated devices are in the resolved-sideband regime. The electric field has its maximum at the slot wall and couples to the in-plane breathing motion of the slot. The optomechanical coupling is thus dominated by the moving-boundary effect, which we simulate to be six times greater than the photoelastic effect, in contrast to most structures, where the photoelastic effect is often the primary coupling mechanism.
Cavity optomechanics in gallium phosphide microdisks
NASA Astrophysics Data System (ADS)
Mitchell, Matthew; Hryciw, Aaron C.; Barclay, Paul E.
2014-04-01
We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8 × 105 and mode volumes <10(λ/n)3, and study their nonlinear and optomechanical properties. For optical intensities up to 8.0 × 104 intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5 μm and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g0/2π˜30 kHz for the fundamental mechanical radial breathing mode at 488 MHz.
Cavity optomechanics in gallium phosphide microdisks
Mitchell, Matthew; Barclay, Paul E.; Hryciw, Aaron C.
2014-04-07
We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8 × 10{sup 5} and mode volumes <10(λ/n){sup 3}, and study their nonlinear and optomechanical properties. For optical intensities up to 8.0 × 10{sup 4} intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5 μm and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g{sub 0}/2π∼30 kHz for the fundamental mechanical radial breathing mode at 488 MHz.
Phase and amplitude dynamics of nonlinearly coupled oscillators
NASA Astrophysics Data System (ADS)
Cudmore, P.; Holmes, C. A.
2015-02-01
This paper addresses the amplitude and phase dynamics of a large system of nonlinearly coupled, non-identical damped harmonic oscillators, which is based on recent research in coupled oscillation in optomechanics. Our goal is to investigate the existence and stability of collective behaviour which occurs due to a play-off between the distribution of individual oscillator frequency and the type of nonlinear coupling. We show that this system exhibits synchronisation, where all oscillators are rotating at the same rate, and that in the synchronised state the system has a regular structure related to the distribution of the frequencies of the individual oscillators. Using a geometric description, we show how changes in the non-linear coupling function can cause pitchfork and saddle-node bifurcations which create or destroy stable and unstable synchronised solutions. We apply these results to show how in-phase and anti-phase solutions are created in a system with a bi-modal distribution of frequencies.
Optomechanical Rydberg-atom excitation via dynamic Casimir-Polder coupling.
Antezza, Mauro; Braggio, Caterina; Carugno, Giovanni; Noto, Antonio; Passante, Roberto; Rizzuto, Lucia; Ruoso, Giuseppe; Spagnolo, Salvatore
2014-07-11
We study the optomechanical coupling of a oscillating effective mirror with a Rydberg atomic gas, mediated by the dynamical atom-mirror Casimir-Polder force. This coupling may produce a near-field resonant atomic excitation whose probability scales as ∝(d(2)an(4)t)(2)/z(0)(8), where z(0) is the average atom-surface distance, d the atomic dipole moment, a the mirror's effective oscillation amplitude, n the initial principal quantum number, and t the time. We propose an experimental configuration to realize this system with a cold atom gas trapped at a distance ∼2×10 μm from a semiconductor substrate whose dielectric constant is periodically driven by an external laser pulse, hence realizing an effective mechanical mirror motion due to the periodic change of the substrate from transparent to reflecting. For a parabolic gas shape, this effect is predicted to excite about ∼10(2) atoms of a dilute gas of 10(3) trapped Rydberg atoms with n=75 after about 0.5 μs, which is high enough to be detected in typical Rydberg gas experimental conditions. PMID:25062178
Optomechanical Rydberg-Atom Excitation via Dynamic Casimir-Polder Coupling
NASA Astrophysics Data System (ADS)
Antezza, Mauro; Braggio, Caterina; Carugno, Giovanni; Noto, Antonio; Passante, Roberto; Rizzuto, Lucia; Ruoso, Giuseppe; Spagnolo, Salvatore
2014-07-01
We study the optomechanical coupling of a oscillating effective mirror with a Rydberg atomic gas, mediated by the dynamical atom-mirror Casimir-Polder force. This coupling may produce a near-field resonant atomic excitation whose probability scales as ∝(d2an4t)2/z08, where z0 is the average atom-surface distance, d the atomic dipole moment, a the mirror's effective oscillation amplitude, n the initial principal quantum number, and t the time. We propose an experimental configuration to realize this system with a cold atom gas trapped at a distance ˜2×10 μm from a semiconductor substrate whose dielectric constant is periodically driven by an external laser pulse, hence realizing an effective mechanical mirror motion due to the periodic change of the substrate from transparent to reflecting. For a parabolic gas shape, this effect is predicted to excite about ˜102 atoms of a dilute gas of 103 trapped Rydberg atoms with n =75 after about 0.5 μs, which is high enough to be detected in typical Rydberg gas experimental conditions.
Nano-optomechanical transducer
Rakich, Peter T; El-Kady, Ihab F; Olsson, Roy H; Su, Mehmet Fatih; Reinke, Charles; Camacho, Ryan; Wang, Zheng; Davids, Paul
2013-12-03
A nano-optomechanical transducer provides ultrabroadband coherent optomechanical transduction based on Mach-wave emission that uses enhanced photon-phonon coupling efficiencies by low impedance effective phononic medium, both electrostriction and radiation pressure to boost and tailor optomechanical forces, and highly dispersive electromagnetic modes that amplify both electrostriction and radiation pressure. The optomechanical transducer provides a large operating bandwidth and high efficiency while simultaneously having a small size and minimal power consumption, enabling a host of transformative phonon and signal processing capabilities. These capabilities include optomechanical transduction via pulsed phonon emission and up-conversion, broadband stimulated phonon emission and amplification, picosecond pulsed phonon lasers, broadband phononic modulators, and ultrahigh bandwidth true time delay and signal processing technologies.
Optical nonreciprocity and optomechanical circulator in three-mode optomechanical systems
NASA Astrophysics Data System (ADS)
Xu, Xun-Wei; Li, Yong
2015-05-01
We demonstrate the possibility of optical nonreciprocal response in a three-mode optomechanical system where one mechanical mode is optomechanically coupled to two linearly coupled optical modes simultaneously. The optical nonreciprocal behavior is induced by the phase difference between the two optomechanical coupling rates, which breaks the time-reversal symmetry of the three-mode optomechanical system. Moreover, the three-mode optomechanical system can also be used as a three-port circulator for two optical modes and one mechanical mode, which we refer to as an optomechanical circulator.
Schneider, Katharina; Seidler, Paul
2016-06-27
We describe the design, fabrication, and characterization of a one-dimensional silicon photonic crystal cavity in which a central slot is used to enhance the overlap between highly localized optical and mechanical modes. The optical mode has an extremely small mode volume of 0.017(λ_{vac} / n)^{3}, and an optomechanical vacuum coupling rate of 310 kHz is measured for a mechanical mode at 2.69 GHz. With optical quality factors up to 1.2 × 10^{5}, fabricated devices are in the resolved-sideband regime. The electric field has its maximum at the slot wall and couples to the in-plane breathing motion of the slot. The optomechanical coupling is thus dominated by the moving-boundary effect, which we simulate to be six times greater than the photoelastic effect, in contrast to most structures, where the photoelastic effect is often the primary coupling mechanism. PMID:27410548
NASA Astrophysics Data System (ADS)
Ma, Yong-Hong; Li, Feng-Zhi; Han, Xiang-Gang; Wu, E.
2016-05-01
We propose a scheme for the realization of a hybrid, strongly entangled system formed of an atomic ensemble surrounded by a quadratically coupled optomechanical cavity with a vibrating mirror. We firstly investigate the steady-state bipartite entanglement between the movable mirror and the cavity mode with the help of an atomic media. It shows that the introduction of the atomic medium can greatly improve the entanglement between the movable mirror and the cavity mode. Secondly, steady-state tripartite entanglement including the movable mirror, the cavity and atom media are investigated. We find the robust tripartite entanglement persists in the present system.
Optomechanical interactions in non-Hermitian photonic molecules
NASA Astrophysics Data System (ADS)
Schönleber, D. W.; Eisfeld, A.; El-Ganainy, R.
2016-04-01
We study optomechanical interactions in non-Hermitian photonic molecules that support two photonic states and one acoustic mode. The nonlinear steady-state solutions and their linear stability landscapes are investigated as a function of the system’s parameters and excitation power levels. We also examine the temporal evolution of the system and uncover different regimes of nonlinear dynamics. Our analysis reveals several important results: (1) parity-time ({ P }{ T }) symmetry is not necessarily the optimum choice for maximum optomechanical interaction. (2) Stable steady-state solutions are not always reached under continuous wave optical excitations. (3) Accounting for gain saturation effects can regulate the behavior of the otherwise unbounded oscillation amplitudes. Our study provides a deeper insight into the interplay between optical non-Hermiticity and optomechanical coupling and can thus pave the way for new device applications.
Quantum optomechanical heat engine.
Zhang, Keye; Bariani, Francesco; Meystre, Pierre
2014-04-18
We investigate theoretically a quantum optomechanical realization of a heat engine. In a generic optomechanical arrangement the optomechanical coupling between the cavity field and the oscillating end mirror results in polariton normal mode excitations whose character depends on the pump detuning and the coupling strength. By varying that detuning it is possible to transform their character from phononlike to photonlike, so that they are predominantly coupled to the thermal reservoir of phonons or photons, respectively. We exploit the fact that the effective temperatures of these two reservoirs are different to produce an Otto cycle along one of the polariton branches. We discuss the basic properties of the system in two different regimes: in the optical domain it is possible to extract work from the thermal energy of a mechanical resonator at finite temperature, while in the microwave range one can in principle exploit the cycle to extract work from the blackbody radiation background coupled to an ultracold atomic ensemble. PMID:24785017
Forced and self-excited oscillations of an optomechanical cavity.
Zaitsev, Stav; Pandey, Ashok K; Shtempluck, Oleg; Buks, Eyal
2011-10-01
We experimentally study forced and self-excited oscillations of an optomechanical cavity, which is formed between a fiber Bragg grating that serves as a static mirror and a freely suspended metallic mechanical resonator that serves as a moving mirror. In the domain of small amplitude mechanical oscillations, we find that the optomechanical coupling is manifested as changes in the effective resonance frequency, damping rate, and cubic nonlinearity of the mechanical resonator. Moreover, self-excited oscillations of the micromechanical mirror are observed above a certain optical power threshold. A comparison between the experimental results and a theoretical model that we have recently derived and analyzed yields a good agreement. The comparison also indicates that the dominant optomechanical coupling mechanism is the heating of the metallic mirror due to optical absorption. PMID:22181294
Intermittency in an optomechanical cavity near a subcritical Hopf bifurcation
NASA Astrophysics Data System (ADS)
Suchoi, Oren; Ella, Lior; Shtempluk, Oleg; Buks, Eyal
2014-09-01
We experimentally study an optomechanical cavity consisting of an oscillating mechanical resonator embedded in a superconducting microwave transmission line cavity. Tunable optomechanical coupling between the mechanical resonator and the microwave cavity is introduced by positioning a niobium-coated single-mode optical fiber above the mechanical resonator. The capacitance between the mechanical resonator and the coated fiber gives rise to optomechanical coupling, which can be controlled by varying the fiber-resonator distance. We study radiation-pressure-induced self-excited oscillation as a function of microwave driving parameters (frequency and power). Intermittency between limit-cycle and steady-state behaviors is observed with blue-detuned driving frequency. The experimental results are accounted for by a model that takes into account the Duffing-like nonlinearity of the microwave cavity. A stability analysis reveals a subcritical Hopf bifurcation near the region where intermittency is observed.
Parametric down-conversion and polariton pair generation in optomechanical systems.
Liu, Yong-Chun; Xiao, Yun-Feng; Chen, You-Ling; Yu, Xiao-Chong; Gong, Qihuang
2013-08-23
We demonstrate that the nonlinear optomechanical interaction leads to parametric down-conversion, capable of generating polariton pairs formed by photons and phonons. The nonlinearity is resonantly enhanced through frequency matching, and such parametric down-conversion does not require the stringent condition that the single-photon optomechanical coupling strength g be on the order of the mechanical resonance frequency ω(m). We provide analytical results for the frequency matching condition and derive the nonlinear coefficient. Numerical simulations on polariton pair generation are presented, showing that photonlike polaritons, phononlike polaritons, and mixed photon-phonon polaritons can be selectively generated. Such nonlinear interaction offers a promising way for harnessing the optomechanical nonlinearity to manipulate photons and phonons. PMID:24010437
Cavity optomechanics mediated by a quantum two-level system
NASA Astrophysics Data System (ADS)
Pirkkalainen, J.-M.; Cho, S. U.; Massel, F.; Tuorila, J.; Heikkilä, T. T.; Hakonen, P. J.; Sillanpää, M. A.
2015-04-01
Coupling electromagnetic waves in a cavity and mechanical vibrations via the radiation pressure of photons is a promising platform for investigations of quantum-mechanical properties of motion. A drawback is that the effect of one photon tends to be tiny, and hence one of the pressing challenges is to substantially increase the interaction strength. A novel scenario is to introduce into the setup a quantum two-level system (qubit), which, besides strengthening the coupling, allows for rich physics via strongly enhanced nonlinearities. Here we present a design of cavity optomechanics in the microwave frequency regime involving a Josephson junction qubit. We demonstrate boosting of the radiation-pressure interaction by six orders of magnitude, allowing to approach the strong coupling regime. We observe nonlinear phenomena at single-photon energies, such as an enhanced damping attributed to the qubit. This work opens up nonlinear cavity optomechanics as a plausible tool for the study of quantum properties of motion.
Cavity optomechanics mediated by a quantum two-level system
Pirkkalainen, J.-M.; Cho, S.U.; Massel, F.; Tuorila, J.; Heikkilä, T.T.; Hakonen, P.J.; Sillanpää, M.A.
2015-01-01
Coupling electromagnetic waves in a cavity and mechanical vibrations via the radiation pressure of photons is a promising platform for investigations of quantum–mechanical properties of motion. A drawback is that the effect of one photon tends to be tiny, and hence one of the pressing challenges is to substantially increase the interaction strength. A novel scenario is to introduce into the setup a quantum two-level system (qubit), which, besides strengthening the coupling, allows for rich physics via strongly enhanced nonlinearities. Here we present a design of cavity optomechanics in the microwave frequency regime involving a Josephson junction qubit. We demonstrate boosting of the radiation–pressure interaction by six orders of magnitude, allowing to approach the strong coupling regime. We observe nonlinear phenomena at single-photon energies, such as an enhanced damping attributed to the qubit. This work opens up nonlinear cavity optomechanics as a plausible tool for the study of quantum properties of motion. PMID:25912295
Ultrastrong optomechanics incorporating the dynamical Casimir effect
NASA Astrophysics Data System (ADS)
Nation, P. D.; Suh, J.; Blencowe, M. P.
2016-02-01
We propose a superconducting circuit comprising a dc superconducting quantum interference device with a mechanically compliant arm embedded in a coplanar microwave cavity that realizes an optomechanical system with a degenerate or nondegenerate parametric interaction generated via the dynamical Casimir effect. For experimentally feasible parameters, this setup is capable of reaching the single-photon ultrastrong-coupling regime while simultaneously possessing a parametric coupling strength approaching the renormalized cavity frequency. This opens up the possibility of observing the interplay between these two fundamental nonlinearities at the single-photon level.
Fabrication and Testing of Microfluidic Optomechanical Oscillators
Han, Kewen; Kim, Kyu Hyun; Kim, Junhwan; Lee, Wonsuk; Liu, Jing; Fan, Xudong; Carmon, Tal; Bahl, Gaurav
2014-01-01
Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including microresonators. However, because of the increased acoustic radiative losses during direct liquid immersion of optomechanical devices, almost all published optomechanical experiments have been performed in solid phase. This paper discusses a recently introduced hollow microfluidic optomechanical resonator. Detailed methodology is provided to fabricate these ultra-high-Q microfluidic resonators, perform optomechanical testing, and measure radiation pressure-driven breathing mode and SBS-driven whispering gallery mode parametric vibrations. By confining liquids inside the capillary resonator, high mechanical- and optical- quality factors are simultaneously maintained. PMID:24962013
NASA Astrophysics Data System (ADS)
Riva, M.
2012-09-01
The design of astronomical instrument is growing in dimension and complexity following ELT class telescopes. The availability of new structural material like composite ones is asking for more robust and reliable designing numerical tools. This paper wants to show a new opto-mechanical optimization approach developed starting from a previously developed integrated design framework. The Idea is to reduce number of iteration in a multi- variable structural optimization taking advantage of the embedded sensitivity routines that are available both in FEA software and in raytracing ones. This approach provide reduced iteration number mainly in case of high number of structural variable parameters.
Negative nonlinear damping of a multilayer graphene mechanical resonator
NASA Astrophysics Data System (ADS)
Singh, Vibhor; Shevchuk, Olga; Blanter, Ya. M.; Steele, Gary A.
2016-06-01
We experimentally investigate the nonlinear response of a multilayer graphene resonator using a superconducting microwave cavity to detect its motion. The radiation pressure force is used to drive the mechanical resonator in an optomechanically induced transparency configuration. By varying the amplitudes of drive and probe tones, the mechanical resonator can be brought into a nonlinear limit. Using the calibration of the optomechanical coupling, we quantify the mechanical Duffing nonlinearity. By increasing the drive force, we observe a decrease in the mechanical dissipation rate at large amplitudes, suggesting a negative nonlinear damping mechanism in the graphene resonator. Increasing the optomechanical backaction further, we observe instabilities in the mechanical response.
Optomechanical down-conversion
NASA Astrophysics Data System (ADS)
Groeblacher, Simon; Hofer, Sebastian; Wieczorek, Witlef; Vanner, Michael; Hammerer, Klemens; Aspelmeyer, Markus
2011-03-01
One of the central interactions in quantum optics is two-mode squeezing, also known as down-conversion. It has been used in a multitude of pioneering experiments to demonstrate non-classical states of light and it is at the heart of generating quantum entanglement in optical fields. Here we demonstrate first experimental results towards the optomechanical analogue, in which an optical and a mechanical mode interact via a two-mode squeezing operation. In addition, we make use of the fact that large optomechanical coupling strengths provide access to an interaction regime beyond the rotating wave approximation. This allows for simultaneous cooling of the mechanical mode, which will eventually enable the preparation of pure initial mechanical states and is hence an important precondition to achieve the envisioned optomechanical entanglement.
Nonlinear optomechanical detection for Majorana fermions via a hybrid nanomechanical system
2014-01-01
The pursuit for detecting the existence of Majorana fermions is a challenging task in condensed matter physics at present. In this work, we theoretically propose a novel nonlinear optical method for probing Majorana fermions in the hybrid semiconductor/superconductor heterostructure. Our proposal is based on a hybrid system constituted by a quantum dot embedded in a nanomechanical resonator. With this method, the nonlinear optical Kerr effect presents a distinct signature for the existence of Majorana fermions. Further, the vibration of the nanomechanical resonator will enhance the nonlinear optical effect, which makes the Majorana fermions more sensitive to be detected. This proposed method may provide a potential supplement for the detection of Majorana fermions. PMID:24708555
Effect of nonlinear nonlinear coupling to a pure dephasing model
NASA Astrophysics Data System (ADS)
Ge, Li; Zhao, Nan
2015-03-01
We investigate the influence of the nonlinear coupling to the coherence of a pure dephasing model. The total system consists of a qubit and a Bosonic bath, which are coupled by an interaction HI =g1σz ⊗ x +g2σz ⊗x2 with x =1/√{ 2} (a +a†) . It's shown that no matter how small g2 is, the long time behavior of the coherence is significantly changed by the nonlinear coupling for free induction decay (FID), while the effect of g1 can be neglected as long as g1 is much smaller than the enegy splitting of the qubit. In the case that many-pulse dynamical decoupling control is exerted on the qubit, g2 also modulates the oscillation of the coherence. Our results indicate that the nonlinear coupling must be taken into account for long time dynamics.
Mechanical squeezing and photonic anti-bunching in a coupled two-cavity optomechanical system.
Cai, Qiu-Hua; Xiao, Yin; Yu, Ya-Fei; Zhang, Zhi-Ming
2016-09-01
We propose a scheme for generating the squeezing of a mechanical mode and the anti-bunching of photonic modes in an optomechanical system. In this system, there are two photonic modes (the left cavity-mode and the right cavity-mode) and one mechanical mode. Both the left cavity-mode and the right cavity-mode are driven by two lasers, respectively. The power of the driving lasers and the detuning between them play a key role in generating squeezing of the mechanical mode. We find that the squeezing of the mechanical mode can be achieved even at a high temperature by increasing the power of the driving lasers. We also find that the cavity-modes can show photonic anti-bunching under suitable conditions. PMID:27607612
Broadband tuning of optomechanical cavities
NASA Astrophysics Data System (ADS)
Wiederhecker, Gustavo S.; Manipatruni, Sasikanth; Lee, Sunwoo; Lipson, Michal
2011-01-01
We demonstrate broadband tuning of an optomechanical microcavity optical resonance by exploring the large optomechanical coupling of a double-wheel microcavity and its uniquely low mechanical stiffness. Using a pump laser with only 13 mW at telecom wavelengths we show tuning of the silicon nitride microcavity resonances over 32 nm. This corresponds to a tuning power efficiency of only 400 $\\mu$W/nm. By choosing a relatively low optical Q resonance ($\\approx$18,000) we prevent the cavity from reaching the regime of regenerative optomechanical oscillations. The static mechanical displacement induced by optical gradient forces is estimated to be as large as 60 nm.
NASA Astrophysics Data System (ADS)
Rivière, R.; Arcizet, O.; Schliesser, A.; Kippenberg, T. J.
2013-04-01
We developed an apparatus to couple a 50-μm diameter whispering-gallery silica microtoroidal resonator in a helium-4 cryostat using a straight optical tapered-fiber at 1550 nm wavelength. On a top-loading probe specifically adapted for increased mechanical stability, we use a specifically-developed "cryotaper" to optically probe the cavity, allowing thus to record the calibrated mechanical spectrum of the optomechanical system at low temperatures. We then demonstrate excellent thermalization of a 63-MHz mechanical mode of a toroidal resonator down to the cryostat's base temperature of 1.65 K, thereby proving the viability of the cryogenic refrigeration via heat conduction through static low-pressure exchange gas. In the context of optomechanics, we therefore provide a versatile and powerful tool with state-of-the-art performances in optical coupling efficiency, mechanical stability, and cryogenic cooling.
Cavity optomechanics - Manipulating mechanical motion at the quantum level
NASA Astrophysics Data System (ADS)
Nunnenkamp, Andreas
2014-03-01
Cavity optomechanics is a rapidly-growing field in which mechanical degrees of freedom are coupled to modes of the electromagnetic field inside optical or microwave resonators. These devices may lead to ultra-sensitive mass and force sensors, provide long-range interaction between distant qubits, and serve as probes of quantum mechanics at increasingly large mass and length scales [for a review see e.g. Physics Today 65, 29 (2012)]. Adapting laser-cooling techniques from atomic physics several experiments have recently observed mechanical motion close to the quantum ground-state. This paves the way for exploiting mechanical systems in the quantum regime. In this talk I will address three problems. First, I will demonstrate that signatures of the intrinsically nonlinear interaction between light and mechanical motion in cavity optomechanical systems can be observed even when the cavity line width exceeds the optomechanical coupling [PRL 111, 053603 (2013)]. Second, I will discuss optomechanical systems in which the position of a mechanical oscillator modulates the line width of the cavity [NJP 15, 045017 (2013) and PRA 88, 023850 (2013)]. Finally, I will present a recent study on synchronization in a self-sustained oscillator coupled to an external harmonic drive [arXiv:1307.7044]. Work done in collaboration with Kjetil Børkje, Christoph Bruder, Steven M. Girvin, John D. Teufel, Stefan Walter, and Talitha Weiss.
Baldacci, Lorenzo; Pitanti, Alessandro; Masini, Luca; Arcangeli, Andrea; Colangelo, Francesco; Navarro-Urrios, Daniel; Tredicucci, Alessandro
2016-01-01
We demonstrate the use of a compound optical cavity as linear displacement detector, by measuring the thermal motion of a silicon nitride suspended membrane acting as the external mirror of a near-infrared Littrow laser diode. Fluctuations in the laser optical power induced by the membrane vibrations are collected by a photodiode integrated within the laser, and then measured with a spectrum analyzer. The dynamics of the membrane driven by a piezoelectric actuator is investigated as a function of air pressure and actuator displacement in a homodyne configuration. The high Q-factor (~3.4 · 104 at 8.3 · 10−3 mbar) of the fundamental mechanical mode at ~73 kHz guarantees a detection sensitivity high enough for direct measurement of thermal motion at room temperature (~87 pm RMS). The compound cavity system here introduced can be employed as a table-top, cost-effective linear displacement detector for cavity optomechanics. Furthermore, thanks to the strong optical nonlinearities of the laser compound cavity, these systems open new perspectives in the study of non-Markovian quantum properties at the mesoscale. PMID:27538586
Baldacci, Lorenzo; Pitanti, Alessandro; Masini, Luca; Arcangeli, Andrea; Colangelo, Francesco; Navarro-Urrios, Daniel; Tredicucci, Alessandro
2016-01-01
We demonstrate the use of a compound optical cavity as linear displacement detector, by measuring the thermal motion of a silicon nitride suspended membrane acting as the external mirror of a near-infrared Littrow laser diode. Fluctuations in the laser optical power induced by the membrane vibrations are collected by a photodiode integrated within the laser, and then measured with a spectrum analyzer. The dynamics of the membrane driven by a piezoelectric actuator is investigated as a function of air pressure and actuator displacement in a homodyne configuration. The high Q-factor (~3.4 · 10(4) at 8.3 · 10(-3) mbar) of the fundamental mechanical mode at ~73 kHz guarantees a detection sensitivity high enough for direct measurement of thermal motion at room temperature (~87 pm RMS). The compound cavity system here introduced can be employed as a table-top, cost-effective linear displacement detector for cavity optomechanics. Furthermore, thanks to the strong optical nonlinearities of the laser compound cavity, these systems open new perspectives in the study of non-Markovian quantum properties at the mesoscale. PMID:27538586
Quantum Optomechanics with Silicon Nanostructures
NASA Astrophysics Data System (ADS)
Safavi-Naeini, Amir H.
Mechanical resonators are the most basic and ubiquitous physical systems known. In on-chip form, they are used to process high frequency signals in every cell phone, television, and laptop. They have also been in the last few decades in different shapes and forms, a critical part of progress in quantum information sciences with kilogram scale mirrors for gravitational wave detection measuring motion at its quantum limits, and the motion of single ions being used to link qubits for quantum computation. Optomechanics is a field primarily concerned with coupling light to the motion of mechanical structures. This thesis contains descriptions of recent work with mechanical systems in the megahertz to gigahertz frequency range, formed by nanofabricating novel photonic/phononic structures on a silicon chip. These structures are designed to have both optical and mechanical resonances, and laser light is used to address and manipulate their motional degrees of freedom through radiation pressure forces. We laser cool these mechanical resonators to their ground states, and observe for the first time the quantum zero-point motion of a nanomechanical resonator. Conversely, we show that engineered mechanical resonances drastically modify the optical response of our structures, creating large effective optical nonlinearities not present in bulk silicon. We experimentally demonstrate aspects of these nonlinearities by proposing and observing ``electromagnetically induced transparency'' and light slowed down to 6 m/s, as well as wavelength conversion, and generation of nonclassical optical radiation. Finally, the application of optomechanics to longstanding problems in quantum and classical communications are proposed and investigated.
Spatiotemporal coupling in dispersive nonlinear planar waveguides
NASA Astrophysics Data System (ADS)
Ryan, Andrew T.; Agrawal, Govind P.
1995-12-01
The multidimensional nonlinear Schrodinger equation governs the spatial and temporal evolution of an optical field inside a nonlinear dispersive medium. Although spatial (diffractive) and temporal (dispersive) effects can be studied independently in a linear medium, they become mutually coupled in a nonlinear medium. We present the results of numerical simulations showing this spatiotemporal coupling for ultrashort pulses propagating in dispersive Kerr media. We investigate how spatiotemporal coupling affects the behavior of the optical field in each of the four regimes defined by the type of group-velocity dispersion (normal or anomalous) and the type of nonlinearity (focusing or defocusing). We show that dispersion, through spatiotemporal coupling, can either enhance or suppress self-focusing and self-defocusing. Similarly, we demonstrate that diffraction can either enhance or suppress pulse compression or broadening. We also discuss how these effects can be controlled with optical phase modulation, such as that provided by a lens (spatial phase modulation) or frequency chirping (temporal phase modulation). Copyright (c) 1995 Optical Society of America
Single-polariton optomechanics.
Restrepo, Juan; Ciuti, Cristiano; Favero, Ivan
2014-01-10
This Letter investigates a hybrid quantum system combining cavity quantum electrodynamics and optomechanics. The Hamiltonian problem of a photon mode coupled to a two-level atom via a Jaynes-Cummings coupling and to a mechanical mode via radiation pressure coupling is solved analytically. The atom-cavity polariton number operator commutes with the total Hamiltonian leading to an exact description in terms of tripartite atom-cavity-mechanics polarons. We demonstrate the possibility to obtain cooling of mechanical motion at the single-polariton level and describe the peculiar quantum statistics of phonons in such an unconventional regime. PMID:24483897
Solitary waves in nonlinear coupled incommensurate chains
NASA Astrophysics Data System (ADS)
Dikandé, A. M.; Kofané, T. C.
1994-01-01
We present dynamical theory of soliton excitations in nonlinear coupled incommensurate chains which consists of two deformable chains of different atomic species, each with its own chemical potential, on the same substrate. In the continuum approximation, the motion equations are a set of coupled Sine-Gordon equations. The soliton solutions of these coupled equations are studied in detail. It has been shown that the frequency of the internal oscillations depends on the coupling parameter. The interaction energy between the two weakly coupled Sine-Gordon systems has been found. Results of the dynamical theory have been related to the transport properties in organic conductors such as TTF-TCNQ, KCP and others. Indeed, we have calculated some meaningful physical parameters of these compounds within the soliton limit, and discussed different types of behaviors shown at the transition with respect to variations of the physical parameters.
Molecular cavity optomechanics as a theory of plasmon-enhanced Raman scattering
NASA Astrophysics Data System (ADS)
Roelli, Philippe; Galland, Christophe; Piro, Nicolas; Kippenberg, Tobias J.
2016-02-01
The exceptional enhancement of Raman scattering by localized plasmonic resonances in the near field of metallic nanoparticles, surfaces or tips (SERS, TERS) has enabled spectroscopic fingerprinting down to the single molecule level. The conventional explanation attributes the enhancement to the subwavelength confinement of the electromagnetic field near nanoantennas. Here, we introduce a new model that also accounts for the dynamical nature of the plasmon-molecule interaction. We thereby reveal an enhancement mechanism not considered before: dynamical backaction amplification of molecular vibrations. We first map the system onto the canonical Hamiltonian of cavity optomechanics, in which the molecular vibration and the plasmon are parametrically coupled. We express the vacuum optomechanical coupling rate for individual molecules in plasmonic ‘hot-spots’ in terms of the vibrational mode's Raman activity and find it to be orders of magnitude larger than for microfabricated optomechanical systems. Remarkably, the frequency of commonly studied molecular vibrations can be comparable to or larger than the plasmon's decay rate. Together, these considerations predict that an excitation laser blue-detuned from the plasmon resonance can parametrically amplify the molecular vibration, leading to a nonlinear enhancement of Raman emission that is not predicted by the conventional theory. Our optomechanical approach recovers known results, provides a quantitative framework for the calculation of cross-sections, and enables the design of novel systems that leverage dynamical backaction to achieve additional, mode-selective enhancements. It also provides a quantum mechanical framework to analyse plasmon-vibrational interactions in terms of molecular quantum optomechanics.
Nonlinearly Coupled Superconducting Lumped Element Resonators
NASA Astrophysics Data System (ADS)
Collodo, Michele C.; Potočnik, Anton; Rubio Abadal, Antonio; Mondal, Mintu; Oppliger, Markus; Wallraff, Andreas
We study SQUID-mediated tunable coupling between two superconducting on-chip resonators in the microwave frequency range. In this circuit QED implementation, we employ lumped-element type resonators, which consist of Nb thin film structured into interdigitated finger shunt capacitors and meander inductors. A SQUID, functioning as flux dependent and intrinsically nonlinear inductor, is placed as a coupling element together with an interdigitated capacitor between the two resonators (cf. A. Baust et al., Phys Rev. B 91 014515 (2015)). We perform a spectroscopic measurement in a dilution refrigerator and find the linear photon hopping rate between the resonators to be widely tunable as well as suppressible for an appropriate choice of parameters, which is made possible due to the interplay of inductively and capacitively mediated coupling. Vanishing linear coupling promotes nonlinear effects ranging from onsite- to cross-Kerr interaction. A dominating cross-Kerr interaction related to this configuration is notable, as it induces a unique quantum state. In the course of analog quantum simulations, such elementary building blocks can serve as a precursor for more complex geometries and thus pave the way to a number of novel quantum phases of light
NASA Astrophysics Data System (ADS)
Vervaeke, Michael; Moens, Els; Meuret, Youri; Ottevaere, Heidi; Van Buggenhout, Carl; De Pauw, Piet; Thienpont, Hugo
2010-05-01
The advent of Plastic Optical Fibre (POF) opened perspectives for numerous applications in the field of datacommunications. POF is increasingly popular in the automotive industry as a robust, lightweight, electromagnetic interference free, easy and cheap to install alternative to electrical wiring for high-speed entertainment, navigation and data acquisition systems in cars. The main challenge for the introduction of datacommunication systems based on POF is imposed by the working conditions of automotive applications: systems should remain fully functional in a temperature range from -40 °C to +115 °C . Furthermore, standardisation and mechanical design considerations put a number of other boundary conditions. We designed a misalignment-tolerant optical coupling system according to the Media Oriented Systems Transport standard (MOST) to convey the divergent beam from a Resonant Cavity Light Emitting Diode (RCLED) into a Step-Index (SI) multimode POF mounted in a detachable ferrule. In this contribution we describe the methodology to synthesize the dimensions and tolerances on the optical components in the coupling system. A Monte Carlo optimisation algorithm on the full three-dimensional (3D) description of the complete RCLED package and detachable POF ferrule was used to allow a realistic modelling of all misalignments that could occur in the production chain. We select the best suited system according to manufacturing and assembly capabilities as well as its suitability for automotive applications.
Coupled oscillator model for nonlinear gravitational perturbations
NASA Astrophysics Data System (ADS)
Yang, Huan; Zhang, Fan; Green, Stephen R.; Lehner, Luis
2015-04-01
Motivated by the gravity-fluid correspondence, we introduce a new method for characterizing nonlinear gravitational interactions. Namely we map the nonlinear perturbative form of the Einstein equation to the equations of motion of a collection of nonlinearly coupled harmonic oscillators. These oscillators correspond to the quasinormal or normal modes of the background spacetime. We demonstrate the mechanics and the utility of this formalism within the context of perturbed asymptotically anti-de Sitter black brane spacetimes. We confirm in this case that the boundary fluid dynamics are equivalent to those of the hydrodynamic quasinormal modes of the bulk spacetime. We expect this formalism to remain valid in more general spacetimes, including those without a fluid dual. In other words, although born out of the gravity-fluid correspondence, the formalism is fully independent and it has a much wider range of applicability. In particular, as this formalism inspires an especially transparent physical intuition, we expect its introduction to simplify the often highly technical analytical exploration of nonlinear gravitational dynamics.
Quantum Optomechanical Heat Engine
NASA Astrophysics Data System (ADS)
Zhang, Keye; Bariani, Francesco; Meystre, Pierre
2014-05-01
We investigate theoretically a quantum optomechanical realization of a heat engine. The coupling between the cavity field and the mechanical resonator results in normal mode excitations whose quantum character depends on the pump detuning and on the coupling strength. By varying that detuning it is possible to transform their character from predominantly phonon-like into photon-like modes of different frequencies and coupled to two thermal reservoirs at different temperatures. We exploit this property to propose an Otto cycle along one branch of the normal modes and calculate its total work and efficiency. We discuss basic properties of that scheme for different optomechanical systems: in the optical domain it is possible to extract work from the thermal energy of a mechanical resonator, while in the microwave range one can in principle exploit the cycle to extract work from the blackbody radiation background coupled to an ultra-cold atomic ensemble. We ackowledge financial support from National Basic Research Program of China, NSF, ARO and the DARPA QuaSAR and ORCHID programs.
Coupled Oscillator Model for Nonlinear Gravitational Perturbations
NASA Astrophysics Data System (ADS)
Yang, Huan; Zhang, Fan; Green, Stephen; Lehner, Luis
2015-04-01
Motivated by the fluid/gravity correspondence, we introduce a new method for characterizing nonlinear gravitational interactions. Namely we map the nonlinear perturbative form of the Einstein's equation to the equations of motion of a series of nonlinearly-coupled harmonic oscillators. These oscillators correspond to the quasinormal modes of the background spacetime. We demonstrate the mechanics and the utility of this formalism with an asymptotically AdS black-brane spacetime, where the equations of motion for the oscillators are shown to be equivalent to the Navier-Stokes equation for the boundary fluid in the mode-expansion picture. We thereby expand on the explicit correspondence connecting the fluid and gravity sides for this particular physical set-up. Perhaps more importantly, we expect this formalism to remain valid in more general spacetimes, including those without a fluid/gravity correspondence. In other words, although born out of the correspondence, the formalism survives independently of it and has a much wider range of applicability.
Nonlinearly enhanced sensing in coupled optical microresonators
NASA Astrophysics Data System (ADS)
Wang, Chao
Optical microresonators that confine photons to micron dimensions with low loss at telecommunication wavelengths play an important role in building modern all-optical integrated circuit. Such systems attract a considerable amount of interest because of the compact size and easy fabrication with state-of-art technologies. One can use the microresonators as sensors, optical delay lines, filters, interferometers, and lasers. In this thesis, we investigate nonlinear effects for sensing application in microring resonators. We theoretically analyze the effect of the Kerr index, two-photon absorption, free-carrier absorption, and free-carrier dispersion. In particular, selfphase and cross-phase modulations caused by the Kerr index are shown to lead to a bifurcation of degenerate resonator mode intensities. Using coupled mode equations, we present the transmission properties of our resonator system with nonlinear effects included. New sensing mechanisms based on the nonlinear bistability and bifurcation are proposed to enhance the transmission's sensitivity to perturbations of the resonance frequency of the resonators. This is used to develop models of ultra-sensitive gyroscopes and refractive index sensors for detection of chemical analytes. The bifurcation dramatically enhances the Sagnac phase shift and therefore substantially lowers the minimum detectable rotation rate (< 1deg/hour) in a micro-resonator gyroscope. For index sensing, nonlinearities enhance the resonance frequency shift and a theoretical detection limit of 10-11 RIU is derived assuming common noises in micro-optical systems. In this work, we focus on silicon-on-insulator resonators but we also consider different platforms, including silicon oxynitride, Hydex, and chalcogenide glasses, and discuss the advantages of each. The results we show here highlight novel mechanisms that can be used in practical applications to improve the performance of a microresonator based optical sensor.
Optimal State Estimation for Cavity Optomechanical Systems.
Wieczorek, Witlef; Hofer, Sebastian G; Hoelscher-Obermaier, Jason; Riedinger, Ralf; Hammerer, Klemens; Aspelmeyer, Markus
2015-06-01
We demonstrate optimal state estimation for a cavity optomechanical system through Kalman filtering. By taking into account nontrivial experimental noise sources, such as colored laser noise and spurious mechanical modes, we implement a realistic state-space model. This allows us to obtain the conditional system state, i.e., conditioned on previous measurements, with a minimal least-squares estimation error. We apply this method to estimate the mechanical state, as well as optomechanical correlations both in the weak and strong coupling regime. The application of the Kalman filter is an important next step for achieving real-time optimal (classical and quantum) control of cavity optomechanical systems. PMID:26196621
NASA Astrophysics Data System (ADS)
Coimbatore Balram, Krishna; Davanco, Marcelo; Ilic, B. Robert; Srinivasan, Kartik
Coherent links between the optical, radio frequency (RF), and mechanical domains are critical for applications ranging from quantum state transfer between the RF and optical domains to signal processing in the acoustic domain for microwave photonics. We develop such a piezo optomechanical circuit platform in GaAs, in which localized and interacting 1550 nm photons and 2.4 GHz phonons are combined with photonic and phononic waveguides. GaAs allows us to exploit the photoelastic effect to engineer cavities with strong optomechanical coupling (g0/2 π ~ 1.1 MHz) and the piezoelectric effect to couple RF fields to mechanical motion through surface acoustic waves, which are routed on-chip using phononic crystal waveguides. This platform enables optical readout of electrically-injected mechanical states with an average coherent intracavity phonon number as small as ~0.05 and the ability to drive mechanical motion with equal facility through either the optical or electrical channel. This is used to demonstrate a novel acoustic wave interference effect in which optically-driven motion is completely cancelled by electrically-driven motion, and vice versa. As an application of this, we present time-domain measurements of optically-controlled acoustic pulse propagation. Secondary Affiliation is Maryland Nanocenter, University of Maryland, College Park, MD.
NASA Astrophysics Data System (ADS)
Zhang, Yu-Qing; Zhu, Zhong-Hua; Peng, Zhao-Hui; Jiang, Chun-Lei; Tan, Lei
2016-07-01
We theoretically investigate the single-photon transport in a hybrid atom-optomechanical system embedded with two dipole-coupled two-level atoms, interacting with a single-mode optical waveguide. The transmission amplitudes for the single-photon propagation in such a hybrid system are obtained via a real-space approach. It is shown that the dipole-dipole interaction can significantly change the amplitudes and symmetries of the single-photon spectra. Interestingly, we find that the dipole-dipole interaction plays a similar role as does the positive atom-cavity detuning. In addition, the influence from the atomic dissipation can be weakened by increasing the dipole-dipole interaction.
Quadratic Measurement and Conditional State Preparation in an Optomechanical System
NASA Astrophysics Data System (ADS)
Brawley, George; Vanner, Michael; Bowen, Warwick; Schmid, Silvan; Boisen, Anja
2014-03-01
An important requirement in the study of quantum systems is the ability to measure non-linear observables at the level of quantum fluctuations. Such measurements enable the conditional preparation of highly non-classical states. Nonlinear measurement, although achieved in a variety of quantum systems including microwave cavity modes and optical fields, remains an outstanding problem in both electromechanical and optomechanical systems. To the best of our knowledge, previous experimental efforts to achieve nonlinear measurement of mechanical motion have not yielded strong coupling, nor the observation of quadratic mechanical motion. Here using a new technique reliant on the intrinsic nonlinearity of the optomechanical interaction, we experimentally observe for the first time a position squared (x2) measurement of the room-temperature Brownian motion of a nanomechanical oscillator. We utilize this measurement to conditionally prepare non-Gaussian bimodal states, which are the high temperature classical analogue of quantum macroscopic superposition states, or cat states. In the future with the aid of cryogenics and state-of-the-art optical cavities, our approach will provide a viable method of generating quantum superposition states of mechanical oscillators. This research was funded by the ARC Center of Excellence for Engineered Quantum Systems.
Nonlinear interaction of meta-atoms through optical coupling
Slobozhanyuk, A. P.; Kapitanova, P. V.; Filonov, D. S.; Belov, P. A.; Powell, D. A.; Shadrivov, I. V.; Kivshar, Yu. S.; Lapine, M.; McPhedran, R. C.
2014-01-06
We propose and experimentally demonstrate a multi-frequency nonlinear coupling mechanism between split-ring resonators. We engineer the coupling between two microwave resonators through optical interaction, whilst suppressing the direct electromagnetic coupling. This allows for a power-dependent interaction between the otherwise independent resonators, opening interesting opportunities to address applications in signal processing, filtering, directional coupling, and electromagnetic compatibility.
Phoxonic crystals and cavity optomechanics
NASA Astrophysics Data System (ADS)
Djafari-Rouhani, Bahram; El-Jallal, Said; Pennec, Yan
2016-05-01
Phoxonic crystals are dual phononic/photonic crystals exhibiting simultaneously band gaps for both types of excitations. Therefore, they have the ability to confine phonons and photons in the same cavity and in turn allow the enhancement of their interaction. In this paper, we review some of our theoretical works on cavity optomechanical interactions in different types of phoxonic crystals, including two-dimensional, slab, and nanobeam structures. Two mechanisms are behind the phonon-photon interaction, namely the photoelastic and the moving interface effects. Coupling rates of a few MHz are obtained with high-frequency phonons of a few GHz. Finally, we give some preliminary results about the optomechanical interaction when a metallic nanoparticle is introduced into the cavity, giving rise to coupled photon-plasmon modes or, in the case of very small particles, to an enhancement of the electric field at the position of the particle. xml:lang="fr"
Optomechanical Metamaterials: Dirac polaritons, Gauge fields, and Instabilities
NASA Astrophysics Data System (ADS)
Peano, Vittorio; Schmidt, Michael; Marquardt, Florian
2014-03-01
Freestanding photonic crystals can be used to trap both light and mechanical vibrations. These ``optomechanical crystal'' structures have already been experimentally demonstrated to yield strong coupling between a photon mode and a phonon mode, co-localized at a single defect site. Future devices may feature a regular superlattice of such defects, turning them into ``optomechanical arrays.'' We predict that tailoring the optomechanical band structure of such arrays can be used to implement Dirac physics of photons and phonons, to create a photonic gauge field via mechanical vibrations, and to observe a novel optomechanical instability. ERC Starting Grant OPTOMECH and via the DARPA program ORCHID.
Silicon Integrated Cavity Optomechanical Transducer
NASA Astrophysics Data System (ADS)
Zou, Jie; Miao, Houxun; Michels, Thomas; Liu, Yuxiang; Srinivasan, Kartik; Aksyuk, Vladimir
2013-03-01
Cavity optomechanics enables measurements of mechanical motion at the fundamental limits of precision imposed by quantum mechanics. However, the need to align and couple devices to off-chip optical components hinders development, miniaturization and broader application of ultrahigh sensitivity chip-scale optomechanical transducers. Here we demonstrate a fully integrated and optical fiber pigtailed optomechanical transducer with a high Q silicon micro-disk cavity near-field coupled to a nanoscale cantilever. We detect the motion of the cantilever by measuring the resonant frequency shift of the whispering gallery mode of the micro-disk. The sensitivity near the standard quantum limit can be reached with sub-uW optical power. Our on-chip approach combines compactness and stability with great design flexibility: the geometry of the micro-disk and cantilever can be tailored to optimize the mechanical/optical Q factors and tune the mechanical frequency over two orders of magnitudes. Electrical transduction in addition to optical transduction was also demonstrated and both can be used to effectively cool the cantilever. Moreover, cantilevers with sharp tips overhanging the chip edge were fabricated to potentially allow the mechanical cantilever to be coupled to a wide range of off-chip systems, such as spins, DNA, nanostructures and atoms on clean surfaces.
Choi, Seung Tae; Son, Byeong Soo; Seo, Gye Won; Park, Si-Young; Lee, Kyung-Sick
2014-03-10
Nonlinear large deformation of a transparent elastomer membrane under hydraulic pressure was analyzed to investigate its optical performance for a variable-focus liquid-filled membrane microlens. In most membrane microlenses, actuators control the hydraulic pressure of optical fluid so that the elastomer membrane together with the internal optical fluid changes its shape, which alters the light path of the microlens to adapt its optical power. A fluid-structure interaction simulation was performed to estimate the transient behavior of the microlens under the operation of electroactive polymer actuators, demonstrating that the viscosity of the optical fluid successfully stabilizes the fluctuations within a fairly short period of time during dynamic operations. Axisymmetric nonlinear plate theory was used to calculate the deformation profile of the membrane under hydrostatic pressure, with which optical characteristics of the membrane microlens were estimated. The effects of gravitation and viscoelastic behavior of the elastomer membrane on the optical performance of the membrane microlens were also evaluated with finite element analysis. PMID:24663947
Optomechanic interactions in phoxonic cavities
Djafari-Rouhani, Bahram; Oudich, Mourad; Pennec, Yan; El-Jallal, Said
2014-12-15
Phoxonic crystals are periodic structures exhibiting simultaneous phononic and photonic band gaps, thus allowing the confinement of both excitations in the same cavity. The phonon-photon interaction can be enhanced due to the overlap of both waves in the cavity. In this paper, we discuss some of our recent theoretical works on the strength of the optomechanic coupling, based on both photoelastic and moving interfaces mechanisms, in different (2D, slabs, strips) phoxonic crystals cavities. The cases of two-dimensional infinite and slab structures will enable us to mention the important role of the symmetry and degeneracy of the modes, as well as the role of the materials whose photoelastic constants can be wavelength dependent. Depending on the phonon-photon pair, the photoelastic and moving interface mechanisms can contribute in phase or out-of-phase. Then, the main part of the paper will be devoted to the optomechanic interaction in a corrugated nanobeam waveguide exhibiting dual phononic/photonic band gaps. Such structures can provide photonic modes with very high quality factor, high frequency phononic modes of a few GHz inside a gap and optomechanical coupling rate reaching a few MHz.
Single-photon quadratic optomechanics
Liao, Jie-Qiao; Nori, Franco
2014-01-01
We present exact analytical solutions to study the coherent interaction between a single photon and the mechanical motion of a membrane in quadratic optomechanics. We consider single-photon emission and scattering when the photon is initially inside the cavity and in the fields outside the cavity, respectively. Using our solutions, we calculate the single-photon emission and scattering spectra, and find relations between the spectral features and the system's inherent parameters, such as: the optomechanical coupling strength, the mechanical frequency, and the cavity-field decay rate. In particular, we clarify the conditions for the phonon sidebands to be visible. We also study the photon-phonon entanglement for the long-time emission and scattering states. The linear entropy is employed to characterize this entanglement by treating it as a bipartite one between a single mode of phonons and a single photon. PMID:25200128
Cavity Optomechanics at Millikelvin Temperatures
NASA Astrophysics Data System (ADS)
Meenehan, Sean Michael
The field of cavity optomechanics, which concerns the coupling of a mechanical object's motion to the electromagnetic field of a high finesse cavity, allows for exquisitely sensitive measurements of mechanical motion, from large-scale gravitational wave detection to microscale accelerometers. Moreover, it provides a potential means to control and engineer the state of a macroscopic mechanical object at the quantum level, provided one can realize sufficiently strong interaction strengths relative to the ambient thermal noise. Recent experiments utilizing the optomechanical interaction to cool mechanical resonators to their motional quantum ground state allow for a variety of quantum engineering applications, including preparation of non-classical mechanical states and coherent optical to microwave conversion. Optomechanical crystals (OMCs), in which bandgaps for both optical and mechanical waves can be introduced through patterning of a material, provide one particularly attractive means for realizing strong interactions between high-frequency mechanical resonators and near-infrared light. Beyond the usual paradigm of cavity optomechanics involving isolated single mechanical elements, OMCs can also be fashioned into planar circuits for photons and phonons, and arrays of optomechanical elements can be interconnected via optical and acoustic waveguides. Such coupled OMC arrays have been proposed as a way to realize quantum optomechanical memories, nanomechanical circuits for continuous variable quantum information processing and phononic quantum networks, and as a platform for engineering and studying quantum many-body physics of optomechanical meta-materials. However, while ground state occupancies (that is, average phonon occupancies less than one) have been achieved in OMC cavities utilizing laser cooling techniques, parasitic absorption and the concomitant degradation of the mechanical quality factor fundamentally limit this approach. On the other hand, the high
Barzanjeh, Sh.; Naderi, M. H.; Soltanolkotabi, M.
2011-12-15
In this paper, we study theoretically bipartite and tripartite continuous variable entanglement as well as normal-mode splitting in a single-atom cavity optomechanical system with intensity-dependent coupling. The system under consideration is formed by a Fabry-Perot cavity with a thin vibrating end mirror and a two-level atom in the Gaussian standing wave of the cavity mode. We first derive the general form of the Hamiltonian describing the tripartite intensity-dependent atom-field-mirror coupling due to the presence of the cavity mode structure. We then restrict our treatment to the first vibrational sideband of the mechanical resonator and derive a tripartite atom-field-mirror Hamiltonian. We show that when the optical cavity is intensely driven, one can generate bipartite entanglement between any pair in the tripartite system and that, due to entanglement sharing, atom-mirror entanglement is efficiently generated at the expense of optical-mechanical and optical-atom entanglement. We also find that in such a system, when the Lamb-Dicke parameter is large enough, one can simultaneously observe the normal mode splitting into three modes.
Inertial Force Coupling to Nonlinear Aeroelasticity of Flexible Wing Aircraft
NASA Technical Reports Server (NTRS)
Nguyen, Nhan T.; Ting, Eric
2016-01-01
This paper investigates the inertial force effect on nonlinear aeroelasticity of flexible wing aircraft. The geometric are nonlinearity due to rotational and tension stiffening. The effect of large bending deflection will also be investigated. Flutter analysis will be conducted for a truss-braced wing aircraft concept with tension stiffening and inertial force coupling.
Unifying Brillouin scattering and cavity optomechanics
NASA Astrophysics Data System (ADS)
Van Laer, Raphaël; Baets, Roel; Van Thourhout, Dries
2016-05-01
So far, Brillouin scattering and cavity optomechanics have been mostly disconnected branches of research, although both deal with photon-phonon coupling. This begs for the development of a broader theory that contains both fields. Here, we derive the dynamics of optomechanical cavities from that of Brillouin-active waveguides. This explicit transition elucidates the link between phenomena such as Brillouin amplification and electromagnetically induced transparency. It proves that effects familiar from cavity optomechanics all have traveling-wave partners, but not vice versa. We reveal a close connection between two parameters of central importance in these fields: the Brillouin gain coefficient and the zero-point optomechanical coupling rate. This enables comparisons between systems as diverse as ultracold atom clouds, plasmonic Raman cavities, and nanoscale silicon waveguides. In addition, back-of-the-envelope calculations show that unobserved effects, such as photon-assisted amplification of traveling phonons, are now accessible in existing systems. Finally, we formulate both circuit- and cavity-oriented optomechanics in terms of vacuum coupling rates, cooperativities, and gain coefficients, thus reflecting the similarities in the underlying physics.
Nonlinear spin wave coupling in adjacent magnonic crystals
NASA Astrophysics Data System (ADS)
Sadovnikov, A. V.; Beginin, E. N.; Morozova, M. A.; Sharaevskii, Yu. P.; Grishin, S. V.; Sheshukova, S. E.; Nikitov, S. A.
2016-07-01
We have experimentally studied the coupling of spin waves in the adjacent magnonic crystals. Space- and time-resolved Brillouin light-scattering spectroscopy is used to demonstrate the frequency and intensity dependent spin-wave energy exchange between the side-coupled magnonic crystals. The experiments and the numerical simulation of spin wave propagation in the coupled periodic structures show that the nonlinear phase shift of spin wave in the adjacent magnonic crystals leads to the nonlinear switching regime at the frequencies near the forbidden magnonic gap. The proposed side-coupled magnonic crystals represent a significant advance towards the all-magnonic signal processing in the integrated magnonic circuits.
Conditional phase gate using an optomechanical resonator
NASA Astrophysics Data System (ADS)
Gea-Banacloche, Julio; Német, Nikolett
2014-05-01
We explore the possibility of using an optomechanical resonator to induce a conditional phase gate for single photons. The problem provides an illustration of the application to optomechanical systems of a recently developed input-output formalism for single- (or few-) photon states of the radiation field. At the two-photon level, we find significant departures from expectations based on a semiclassical treatment. We also find a tradeoff between the maximum achievable conditional phase and the fidelity of the final state, consistent with other multimode studies of conditional phases based on optical nonlinearities.
Nonlinear Walecka models and point-coupling relativistic models
Lourenco, O.; Amaral, R. L. P. G.; Dutra, M.; Delfino, A.
2009-10-15
We study hadronic nonlinear point-coupling (NLPC) models which reproduce numerically the binding energy, the incompressibility, and the nucleon effective mass at the nuclear matter saturation obtained by different nonlinear Walecka (NLW) models. We have investigated their behaviors as functions of the nuclear matter density to observe how they deviate from known NLW models. In our study we present a meson-exchange modified nonlinear Walecka model (MNLW) which exactly underlies a nonlinear point-coupling model (NLPC) presenting third- and fourth-order scalar density self-couplings. A discussion about naive dimensional analysis (NDA) and naturalness is also provided for a large class of NLW and NLPC models. At finite temperature, critical and flash parameters of both approaches are presented.
PT symmetry breaking and nonlinear optical isolation in coupled microcavities
NASA Astrophysics Data System (ADS)
Zhou, Xin; Chong, Y. D.
2016-04-01
We perform a theoretical study of nonlinear optical isolator devices based on coupled microcavities with gain and loss. Using coupled-mode theory, we derive a correspondence between the boundary of asymptotic stability in the nonlinear regime, where gain saturation is present, and the PT-breaking transition in the underlying linear system. For zero detuning and weak input intensity, the onset of optical isolation can be rigorously derived, and corresponds precisely to the PT transition point. When the couplings to the external ports are unequal, the isolation ratio exhibits an abrupt jump at the transition point, determined by the ratio of the couplings. This could be exploited to realize an actively controlled nonlinear optical isolator, in which strong optical isolation can be switched on or off using tiny variations in the inter-resonator separation.
Slow light in nonlinear photonic crystal coupled-cavity waveguides
NASA Astrophysics Data System (ADS)
Zhu, Na; Wang, Yige; Ren, Qingqing; Zhu, Li; Yuan, Minmin; An, Guimin
2014-04-01
Nonlinear photonic crystals can be formed by inserting Kerr-type nonlinear dielectric rods into perfect photonic crystals. Based on nonlinear photonic crystal, nonlinear photonic crystal coupled-cavity waveguide is constructed and its slow light properties are studied by using the Plane Wave expansion Method (PWM). Both single-defect coupled cavity and two-defect coupled cavity are proposed to optimize slow light properties. The result shows that using single-defect coupled cavity in waveguide is beneficial to obtain larger Normalized Delay-Bandwidth Product (NDBP) but it contributes little to decrease the group velocity of light and enlarging Q factor and delay time; While using two-defect cavity in waveguide can efficiently reduce the group velocity of light and enlarge Q factor and delay time. Compared to normal structures, our new designed nonlinear photonic crystal coupled cavity waveguide owns group velocity that is three magnitudes smaller than the vacuum speed of light. Delay time is of magnitude order of 10 ns and Q factor is of magnitude order of 1000, it means less loss and higher ability of storing energy.
Integrated waveguide-DBR microcavity opto-mechanical system.
Pruessner, Marcel W; Stievater, Todd H; Khurgin, Jacob B; Rabinovich, William S
2011-10-24
Cavity opto-mechanics exploits optical forces acting on mechanical structures. Many opto-mechanics demonstrations either require extensive alignment of optical components for probing and measurement, which limits the number of opto-mechanical devices on-chip; or the approaches limit the ability to control the opto-mechanical parameters independently. In this work, we propose an opto-mechanical architecture incorporating a waveguide-DBR microcavity coupled to an in-plane micro-bridge resonator, enabling large-scale integration on-chip with the ability to individually tune the optical and mechanical designs. We experimentally characterize our device and demonstrate mechanical resonance damping and amplification, including the onset of coherent oscillations. The resulting collapse of the resonance linewidth implies a strong increase in effective mechanical quality-factor, which is of interest for high-resolution sensing. PMID:22109043
Nonlinear wave propagation in strongly coupled dusty plasmas.
Veeresha, B M; Tiwari, S K; Sen, A; Kaw, P K; Das, A
2010-03-01
The nonlinear propagation of low-frequency waves in a strongly coupled dusty plasma medium is studied theoretically in the framework of the phenomenological generalized hydrodynamic (GH) model. A set of simplified model nonlinear equations are derived from the original nonlinear integrodifferential form of the GH model by employing an appropriate physical ansatz. Using standard perturbation techniques characteristic evolution equations for finite small amplitude waves are then obtained in various propagation regimes. The influence of viscoelastic properties arising from dust correlation contributions on the nature of nonlinear solutions is discussed. The modulational stability of dust acoustic waves to parallel perturbation is also examined and it is shown that dust compressibility contributions influenced by the Coulomb coupling effects introduce significant modification in the threshold and range of the instability domain. PMID:20365882
Nonlinear wave propagation in strongly coupled dusty plasmas
Veeresha, B. M.; Tiwari, S. K.; Sen, A.; Kaw, P. K.; Das, A.
2010-03-15
The nonlinear propagation of low-frequency waves in a strongly coupled dusty plasma medium is studied theoretically in the framework of the phenomenological generalized hydrodynamic (GH) model. A set of simplified model nonlinear equations are derived from the original nonlinear integrodifferential form of the GH model by employing an appropriate physical ansatz. Using standard perturbation techniques characteristic evolution equations for finite small amplitude waves are then obtained in various propagation regimes. The influence of viscoelastic properties arising from dust correlation contributions on the nature of nonlinear solutions is discussed. The modulational stability of dust acoustic waves to parallel perturbation is also examined and it is shown that dust compressibility contributions influenced by the Coulomb coupling effects introduce significant modification in the threshold and range of the instability domain.
Dynamic stabilization of an optomechanical oscillator
NASA Astrophysics Data System (ADS)
Seok, H.; Wright, E. M.; Meystre, P.
2014-10-01
Quantum optomechanics offers the potential to investigate quantum effects in macroscopic quantum systems in extremely well-controlled experiments. In this paper we discuss one such situation, the dynamic stabilization of a mechanical system such as an inverted pendulum. The specific example that we study is a "membrane-in-the-middle" mechanical oscillator coupled to a cavity field via a quadratic optomechanical interaction, with cavity damping the dominant source of dissipation. We show that the mechanical oscillator can be dynamically stabilized by a temporal modulation of the radiation pressure force. We investigate the system both in the classical and quantum regimes highlighting similarities and differences.
Macroscopic optomechanical superposition via periodic qubit flipping
NASA Astrophysics Data System (ADS)
Ge, Wenchao; Zubairy, M. Suhail
2015-01-01
We propose a scheme to generate macroscopic superpositions of well-distinguishable coherent states in an optomechanical system via periodic qubit flipping. Our scheme does not require the single-photon strong-coupling rate of an optomechanical system. The generated mechanical superposition state can be reconstructed using mechanical quantum-state reconstruction. The proposed scheme relies on recycling of an atom, fast atomic qubit flipping, and coherent state mapping between a single-photon superposition state and an atomic superposition state. We discuss the experimental feasibility of our proposal under current technology.
Sensitivity of cavity optomechanical field sensors
NASA Astrophysics Data System (ADS)
Knittel, J.; Forstner, S.; Swaim, J.; Rubinsztein-Dunlop, H.; Bowen, W. P.
2012-02-01
This article presents a technique for modeling cavity optomechanical field sensors. A magnetic or electric field induces a spatially varying strain across the sensor. The effect of this strain is accounted for by separating the mechanical motion of the sensor into eigenmodes, each modeled by a simple harmonic oscillator. The force induced on each oscillator can then be determined from an overlap integral between strain and the corresponding eigenmode, with the optomechanical coupling strength determining the ultimate resolution with which this force can be detected.
Observing spin optodynamical analog of cavity optomechanics
NASA Astrophysics Data System (ADS)
Gerber, Justin; Kohler, Jonathan; Spethmann, Nicolas; Schreppler, Sydney; Stamper-Kurn, Dan
2016-05-01
Cavity Optomechanics has been realized in many diverse systems and led to many interesting results such as ponderomotive squeezing of light, beyond-SQL measurement sensitivity, and squeezing of mechanical oscillators. Optical cavities also allow sensitive measurements of the spin of an atomic ensemble. It has been proposed to utilize this sensitivity to realize an analog of optomechanics by measuring the precession of small excitations of a spin-oscillator around a transverse magnetic field. I will present our recent work in which we realize optomechanical analogs in our system such as cavity-assisted cooling and amplification and optical spring shifts. In addition, the presence of a high-energy `ground state' of the spin oscillator allows the realization of an effective negative mass oscillator which is demonstrated by an inverted sideband asymmetry. In our ongoing work we attempt to realize coherent quantum noise cancelation by coupling spin oscillation with mechanical oscillation.
Nonlinear wave propagation in a strongly coupled collisional dusty plasma
Ghosh, Samiran; Gupta, Mithil Ranjan; Chakrabarti, Nikhil; Chaudhuri, Manis
2011-06-15
The propagation of a nonlinear low-frequency mode in a strongly coupled dusty plasma is investigated using a generalized hydrodynamical model. For the well-known longitudinal dust acoustic mode a standard perturbative approach leads to a Korteweg-de Vries (KdV) soliton. The strong viscoelastic effect, however, introduced a nonlinear forcing and a linear damping in the KdV equation. This novel equation is solved analytically to show a competition between nonlinear forcing and dissipative damping. The physical consequence of such a solution is also sketched.
Nonlinear wave propagation in a strongly coupled collisional dusty plasma.
Ghosh, Samiran; Gupta, Mithil Ranjan; Chakrabarti, Nikhil; Chaudhuri, Manis
2011-06-01
The propagation of a nonlinear low-frequency mode in a strongly coupled dusty plasma is investigated using a generalized hydrodynamical model. For the well-known longitudinal dust acoustic mode a standard perturbative approach leads to a Korteweg-de Vries (KdV) soliton. The strong viscoelastic effect, however, introduced a nonlinear forcing and a linear damping in the KdV equation. This novel equation is solved analytically to show a competition between nonlinear forcing and dissipative damping. The physical consequence of such a solution is also sketched. PMID:21797497
Non-linear optics of ultrastrongly coupled cavity polaritons
NASA Astrophysics Data System (ADS)
Crescimanno, Michael; Liu, Bin; McMaster, Michael; Singer, Kenneth
2016-05-01
Experiments at CWRU have developed organic cavity polaritons that display world-record vacuum Rabi splittings of more than an eV. This ultrastrongly coupled polaritonic matter is a new regime for exploring non-linear optical effects. We apply quantum optics theory to quantitatively determine various non-linear optical effects including types of low harmonic generation (SHG and THG) in single and double cavity polariton systems. Ultrastrongly coupled photon-matter systems such as these may be the foundation for technologies including low-power optical switching and computing.
Applications of cavity optomechanics
Metcalfe, Michael
2014-09-15
“Cavity-optomechanics” aims to study the quantum properties of mechanical systems. A common strategy implemented in order to achieve this goal couples a high finesse photonic cavity to a high quality factor mechanical resonator. Then, using feedback forces such as radiation pressure, one can cool the mechanical mode of interest into the quantum ground state and create non-classical states of mechanical motion. On the path towards achieving these goals, many near-term applications of this field have emerged. After briefly introducing optomechanical systems and describing the current state-of-the-art experimental results, this article summarizes some of the more exciting practical applications such as ultra-sensitive, high bandwidth accelerometers and force sensors, low phase noise x-band integrated microwave oscillators and optical signal processing such as optical delay-lines, wavelength converters, and tunable optical filters. In this rapidly evolving field, new applications are emerging at a fast pace, but this article concentrates on the aforementioned lab-based applications as these are the most promising avenues for near-term real-world applications. New basic science applications are also becoming apparent such as the generation of squeezed light, testing gravitational theories and for providing a link between disparate quantum systems.
Nonlinear Generalized Hydrodynamic Wave Equations in Strongly Coupled Dusty Plasmas
Veeresha, B. M.; Sen, A.; Kaw, P. K.
2008-09-07
A set of nonlinear equations for the study of low frequency waves in a strongly coupled dusty plasma medium is derived using the phenomenological generalized hydrodynamic (GH) model and is used to study the modulational stability of dust acoustic waves to parallel perturbations. Dust compressibility contributions arising from strong Coulomb coupling effects are found to introduce significant modifications in the threshold and range of the instability domain.
Tunable high-order sideband spectra generation using a photonic molecule optomechanical system
Cao, Cong; Mi, Si-Chen; Gao, Yong-Pan; He, Ling-Yan; Yang, Daquan; Wang, Tie-Jun; Zhang, Ru; Wang, Chuan
2016-01-01
A tunable high-order sideband spectra generation scheme is presented by using a photonic molecule optomechanical system coupled to a waveguide beyond the perturbation regime. The system is coherently driven by a two-tone laser consisting of a continuous-wave control field and a pulsed driving field which propagates through the waveguide. The frequency spectral feature of the output field is analyzed via numerical simulations, and we confirm that under the condition of intense and nanosecond pulse driving, the output spectrum exhibits the properties of high-order sideband frequency spectra. In the experimentally available parameter range, the output spectrum can be efficiently tuned by the system parameters, including the power of the driving pulse and the coupling rate between the cavities. In addition, analysis of the carrier-envelop phase-dependent effect of high-order sideband generation indicates that the system may present dependence upon the phase of the pulse. This may provide a further insight of the properties of cavity optomechanics in the nonlinear and non-perturbative regime, and may have potential applications in optical frequency comb and communication based on the optomechanical platform. PMID:26960430
Tunable high-order sideband spectra generation using a photonic molecule optomechanical system.
Cao, Cong; Mi, Si-Chen; Gao, Yong-Pan; He, Ling-Yan; Yang, Daquan; Wang, Tie-Jun; Zhang, Ru; Wang, Chuan
2016-01-01
A tunable high-order sideband spectra generation scheme is presented by using a photonic molecule optomechanical system coupled to a waveguide beyond the perturbation regime. The system is coherently driven by a two-tone laser consisting of a continuous-wave control field and a pulsed driving field which propagates through the waveguide. The frequency spectral feature of the output field is analyzed via numerical simulations, and we confirm that under the condition of intense and nanosecond pulse driving, the output spectrum exhibits the properties of high-order sideband frequency spectra. In the experimentally available parameter range, the output spectrum can be efficiently tuned by the system parameters, including the power of the driving pulse and the coupling rate between the cavities. In addition, analysis of the carrier-envelop phase-dependent effect of high-order sideband generation indicates that the system may present dependence upon the phase of the pulse. This may provide a further insight of the properties of cavity optomechanics in the nonlinear and non-perturbative regime, and may have potential applications in optical frequency comb and communication based on the optomechanical platform. PMID:26960430
The properties of Stokes and anti-Stokes processes in a double-cavity optomechanical system
NASA Astrophysics Data System (ADS)
Yan, Xiao-Bo; Fu, Chang-Bao; Gu, Kai-Hui; Wang, Rong; Wu, Jin-Hui
2013-11-01
We study the nonlinear Stokes and anti-Stokes processes of a weak probe field relevant to normal mode splitting (NMS) in a double-cavity optomechanical system where a membrane oscillator is shared by two identical cavities. The two cavity modes experience an optomechanical coupling of same amplitudes but opposite signs when the membrane deviates from its equilibrium position due to the radiation pressures arising from two strong pump fields. Our calculations show that the critical power of left-cavity pump field above which the double-cavity system enters the NMS regime can be easily controlled by adjusting the right-cavity pump field in power. In addition, we show that various NMS features can be well examined by focusing on the spectral structure of an anti-Stokes signal generated in the four-wave-mixing process arising from optomechanical coupling. Last but not least we note that the anti-Stokes signal's generation is accompanied by the Stokes signal's amplification (absorption) in the absence (presence) of right-cavity pump field.
Nonlinear matter spectra in coupled quintessence
Saracco, F.; Pietroni, M.; Tetradis, N.; Pettorino, V.; Robbers, G.
2010-07-15
We consider cosmologies in which a dark-energy scalar field interacts with cold dark matter. The growth of perturbations is followed beyond the linear level by means of the time-renormalization-group method, which is extended to describe a multicomponent matter sector. Even in the absence of the extra interaction, a scale-dependent bias is generated as a consequence of the different initial conditions for baryons and dark matter after decoupling. The effect is enhanced significantly by the extra coupling and can be at the 2%-3% level in the range of scales of baryonic acoustic oscillations. We compare our results with N-body simulations, finding very good agreement.
Nonlinearly coupled localized plasmon resonances: Resonant second-harmonic generation
NASA Astrophysics Data System (ADS)
Ginzburg, Pavel; Krasavin, Alexey; Sonnefraud, Yannick; Murphy, Antony; Pollard, Robert J.; Maier, Stefan A.; Zayats, Anatoly V.
2012-08-01
The efficient resonant nonlinear coupling between localized surface plasmon modes is demonstrated in a simple and intuitive way using boundary integral formulation and utilizing second-order optical nonlinearity. The nonlinearity is derived from the hydrodynamic description of electron plasma and originates from the presence of material interfaces in the case of small metal particles. The coupling between fundamental and second-harmonic modes is shown to be symmetry selective and proportional to the spatial overlap between polarization dipole density of the second-harmonic mode and the square of the polarization charge density of the fundamental mode. Particles with high geometrical symmetry will convert a far-field illumination into dark nonradiating second-harmonic modes, such as quadrupoles. Effective second-harmonic susceptibilities are proportional to the surface-to-volume ratio of a particle, emphasizing the nanoscale enhancement of the effect.
A Jacobi collocation approximation for nonlinear coupled viscous Burgers' equation
NASA Astrophysics Data System (ADS)
Doha, Eid; Bhrawy, Ali; Abdelkawy, Mohamed; Hafez, Ramy
2014-02-01
This article presents a numerical approximation of the initial-boundary nonlinear coupled viscous Burgers' equation based on spectral methods. A Jacobi-Gauss-Lobatto collocation (J-GL-C) scheme in combination with the implicit Runge-Kutta-Nyström (IRKN) scheme are employed to obtain highly accurate approximations to the mentioned problem. This J-GL-C method, based on Jacobi polynomials and Gauss-Lobatto quadrature integration, reduces solving the nonlinear coupled viscous Burgers' equation to a system of nonlinear ordinary differential equation which is far easier to solve. The given examples show, by selecting relatively few J-GL-C points, the accuracy of the approximations and the utility of the approach over other analytical or numerical methods. The illustrative examples demonstrate the accuracy, efficiency, and versatility of the proposed algorithm.
Nonlinear Observers for Gyro Calibration Coupled with a Nonlinear Control Algorithm
NASA Technical Reports Server (NTRS)
Thienel, Julie; Sanner, Robert M.
2003-01-01
Nonlinear observers for gyro calibration are presented. The first observer estimates a constant gyro bias. The second observer estimates scale factor errors. The third observer estimates the gyro alignment for three orthogonal gyros. The observers are then combined. The convergence properties of all three observers, and the combined observers, are discussed. Additionally, all three observers are coupled with a nonlinear control algorithm. The stability of each of the resulting closed loop systems is analyzed. Simulated test results are presented for each system.
Current density fluctuations, nonlinear coupling, and transport in MST
Prager, S.C.; Almagri, A.F.; Assadi, S.; Cekic, M.; Chapman, B.E.; Crocker, N.; Den Hartog, D.J.; Dexter, R.N.; Fiksel, G.; Fonck, R.J.; Henry, J.S.; Hokin, S.A.; Holly, D.J.; Ji, H.; Rempel, T.D.; Sarff, J.S.; Scime, E.; Shen, W.; Sidikman, K.L.; Sprott, J.C.; Stoneking, M.R.; Watts, C.
1992-09-01
New information on magnetic fluctuations and transport in toroidal devices has been obtained in the MST reversed field pinch through measurement of nonlinear coupling of three waves in k-space, and measurement of current density fluctuations. Measurements of nonlinear coupling of magnetic fluctuations reveals that (1) two poloidal mode number m = 1 modes couple strongly to an m = 2 mode, (2) toroidal mode coupling is broad extending up to n = 20, (3) these features agree with predictions for tearing fluctuations from a nonlinear MHD code, (4) during a sawtooth crash the number of modes involved in nonlinear interactions increases dramatically and the k-spectrum broadens simultaneously. Measurements of current density fluctuations over the outer 20% of the minor radius reveal that (1) low frequency fluctuations are consistent with tearing modes, (2) high frequency fluctuations are localized turbulence which maintains resonance with the equilibrium field as q changes with radius, (3) particle transport from magnetic fluctuations is ambipolar (i.e., <{delta}j{sub {parallel}}B{sub r}> = O).
Collocation Method for Numerical Solution of Coupled Nonlinear Schroedinger Equation
Ismail, M. S.
2010-09-30
The coupled nonlinear Schroedinger equation models several interesting physical phenomena presents a model equation for optical fiber with linear birefringence. In this paper we use collocation method to solve this equation, we test this method for stability and accuracy. Numerical tests using single soliton and interaction of three solitons are used to test the resulting scheme.
The coupled nonlinear dynamics of a lift system
NASA Astrophysics Data System (ADS)
Crespo, Rafael Sánchez; Kaczmarczyk, Stefan; Picton, Phil; Su, Huijuan
2014-12-01
Coupled lateral and longitudinal vibrations of suspension and compensating ropes in a high-rise lift system are often induced by the building motions due to wind or seismic excitations. When the frequencies of the building become near the natural frequencies of the ropes, large resonance motions of the system may result. This leads to adverse coupled dynamic phenomena involving nonplanar motions of the ropes, impact loads between the ropes and the shaft walls, as well as vertical vibrations of the car, counterweight and compensating sheave. Such an adverse dynamic behaviour of the system endangers the safety of the installation. This paper presents two mathematical models describing the nonlinear responses of a suspension/ compensating rope system coupled with the elevator car / compensating sheave motions. The models accommodate the nonlinear couplings between the lateral and longitudinal modes, with and without longitudinal inertia of the ropes. The partial differential nonlinear equations of motion are derived using Hamilton Principle. Then, the Galerkin method is used to discretise the equations of motion and to develop a nonlinear ordinary differential equation model. Approximate numerical solutions are determined and the behaviour of the system is analysed.
Nonlinear mode coupling in whispering-gallery-mode resonators
NASA Astrophysics Data System (ADS)
D'Aguanno, Giuseppe; Menyuk, Curtis R.
2016-04-01
We present a first-principles derivation of the coupled nonlinear Schrödinger equations that govern the interaction between two families of modes with different transverse profiles in a generic whispering-gallery-mode resonator. We find regions of modulational instability and the existence of trains of bright solitons in both the normal and the anomalous dispersion regime.
The coupled nonlinear dynamics of a lift system
Crespo, Rafael Sánchez E-mail: stefan.kaczmarczyk@northampton.ac.uk E-mail: huijuan.su@northampton.ac.uk; Kaczmarczyk, Stefan E-mail: stefan.kaczmarczyk@northampton.ac.uk E-mail: huijuan.su@northampton.ac.uk; Picton, Phil E-mail: stefan.kaczmarczyk@northampton.ac.uk E-mail: huijuan.su@northampton.ac.uk; Su, Huijuan E-mail: stefan.kaczmarczyk@northampton.ac.uk E-mail: huijuan.su@northampton.ac.uk
2014-12-10
Coupled lateral and longitudinal vibrations of suspension and compensating ropes in a high-rise lift system are often induced by the building motions due to wind or seismic excitations. When the frequencies of the building become near the natural frequencies of the ropes, large resonance motions of the system may result. This leads to adverse coupled dynamic phenomena involving nonplanar motions of the ropes, impact loads between the ropes and the shaft walls, as well as vertical vibrations of the car, counterweight and compensating sheave. Such an adverse dynamic behaviour of the system endangers the safety of the installation. This paper presents two mathematical models describing the nonlinear responses of a suspension/ compensating rope system coupled with the elevator car / compensating sheave motions. The models accommodate the nonlinear couplings between the lateral and longitudinal modes, with and without longitudinal inertia of the ropes. The partial differential nonlinear equations of motion are derived using Hamilton Principle. Then, the Galerkin method is used to discretise the equations of motion and to develop a nonlinear ordinary differential equation model. Approximate numerical solutions are determined and the behaviour of the system is analysed.
Giant nonlinear response from plasmonic metasurfaces coupled to intersubband transitions
NASA Astrophysics Data System (ADS)
Lee, Jongwon; Tymchenko, Mykhailo; Argyropoulos, Christos; Chen, Pai-Yen; Lu, Feng; Demmerle, Frederic; Boehm, Gerhard; Amann, Markus-Christian; Alù, Andrea; Belkin, Mikhail A.
2014-07-01
Intersubband transitions in n-doped multi-quantum-well semiconductor heterostructures make it possible to engineer one of the largest known nonlinear optical responses in condensed matter systems--but this nonlinear response is limited to light with electric field polarized normal to the semiconductor layers. In a different context, plasmonic metasurfaces (thin conductor-dielectric composite materials) have been proposed as a way of strongly enhancing light-matter interaction and realizing ultrathin planarized devices with exotic wave properties. Here we propose and experimentally realize metasurfaces with a record-high nonlinear response based on the coupling of electromagnetic modes in plasmonic metasurfaces with quantum-engineered electronic intersubband transitions in semiconductor heterostructures. We show that it is possible to engineer almost any element of the nonlinear susceptibility tensor of these structures, and we experimentally verify this concept by realizing a 400-nm-thick metasurface with nonlinear susceptibility of greater than 5 × 104 picometres per volt for second harmonic generation at a wavelength of about 8 micrometres under normal incidence. This susceptibility is many orders of magnitude larger than any second-order nonlinear response in optical metasurfaces measured so far. The proposed structures can act as ultrathin highly nonlinear optical elements that enable efficient frequency mixing with relaxed phase-matching conditions, ideal for realizing broadband frequency up- and down-conversions, phase conjugation and all-optical control and tunability over a surface.
Giant nonlinear response from plasmonic metasurfaces coupled to intersubband transitions.
Lee, Jongwon; Tymchenko, Mykhailo; Argyropoulos, Christos; Chen, Pai-Yen; Lu, Feng; Demmerle, Frederic; Boehm, Gerhard; Amann, Markus-Christian; Alù, Andrea; Belkin, Mikhail A
2014-07-01
Intersubband transitions in n-doped multi-quantum-well semiconductor heterostructures make it possible to engineer one of the largest known nonlinear optical responses in condensed matter systems--but this nonlinear response is limited to light with electric field polarized normal to the semiconductor layers. In a different context, plasmonic metasurfaces (thin conductor-dielectric composite materials) have been proposed as a way of strongly enhancing light-matter interaction and realizing ultrathin planarized devices with exotic wave properties. Here we propose and experimentally realize metasurfaces with a record-high nonlinear response based on the coupling of electromagnetic modes in plasmonic metasurfaces with quantum-engineered electronic intersubband transitions in semiconductor heterostructures. We show that it is possible to engineer almost any element of the nonlinear susceptibility tensor of these structures, and we experimentally verify this concept by realizing a 400-nm-thick metasurface with nonlinear susceptibility of greater than 5 × 10(4) picometres per volt for second harmonic generation at a wavelength of about 8 micrometres under normal incidence. This susceptibility is many orders of magnitude larger than any second-order nonlinear response in optical metasurfaces measured so far. The proposed structures can act as ultrathin highly nonlinear optical elements that enable efficient frequency mixing with relaxed phase-matching conditions, ideal for realizing broadband frequency up- and down-conversions, phase conjugation and all-optical control and tunability over a surface. PMID:24990746
Nonlinear coupling of tearing fluctuations in the Madison Symmetric Torus
Sarff, J.S.; Assadi, S.; Almagri, A.F.; Cekic, M.; Den Hartog, D.J.; Fiksel, G.; Hokin, S.A.; Ji, H.; Prager, S.C.; Shen, W.; Sidikman, K.L.; Stoneking, M.R. )
1993-07-01
Three-wave, nonlinear, tearing mode coupling has been measured in the Madison Symmetric Torus (MST) reversed-field pinch (RFP) [Fusion Technol. [bold 19], 131 (1991)] using bispectral analysis of edge magnetic fluctuations resolved in [ital k]-space.'' The strength of nonlinear three-wave interactions satisfying the sum rules [ital m][sub 1]+[ital m][sub 2]=[ital m][sub 3] and [ital n][sub 1]+[ital n][sub 2]=[ital n][sub 3] is measured by the bicoherency. In the RFP, [ital m]=1, [ital n][similar to]2[ital R]/[ital a] (6 for MST) internally resonant modes are linearly unstable and grow to large amplitude. Large values of bicoherency occur for two [ital m]=1 modes coupled to an [ital m]=2 mode and the coupling of intermediate toroidal modes, e.g., [ital n]=6 and 7 coupled to [ital n]=13. These experimental bispectral features agree with predicted bispectral features derived from magnetohydrodynamic (MHD) computation. However, in the experiment, enhanced coupling occurs in the crash'' phase of a sawtooth oscillation concomitant with a broadened mode spectrum suggesting the onset of a nonlinear cascade.
Nonlinear coupling of tearing fluctuations in the Madison Symmetric Torus
Sarff, J.S.; Almagri, A.F.; Cekic, M.; Den Hartog, D.J.; Fiksel, G.; Hokin, S.A.; Ji, H.; Prager, S.C.; Shen, W.; Stoneking, M.R. ); Assadi, S. ); Sidikman, K.L. )
1992-11-01
Three-wave, nonlinear, tearing mode coupling has been measured in the Madison Symmetric Torus (MST) reversed-field pinch (RFP) [Fusion Technol. 19, 131 (1991)] using bispectral analysis of edge magnetic fluctuations resolved in k-space. The strength of nonlinear three-wave interactions satisfying the sum rules m[sub 1] + m[sub 2] = m[sub 3] and n[sub 1] + n[sub 2] = n[sub 3] is measured by the bicoherency. In the RFP, m=l, n[approximately]2R/a (6 for MST) internally resonant modes are linearly unstable and grow to large amplitude. Large values of bicoherency occur for two m=l modes coupled to an m=2 mode and the coupling of intermediate toroidal modes, e.g., n=6 and 7 coupled to n=13. These experimental bispectral features agree with predicted bispectral features derived from MHD computation. However, in the experiment, enhanced coupling occurs in the crash'' phase of a sawtooth oscillation concomitant with a broadened mode spectrum suggesting the onset of a nonlinear cascade.
Nonlinear coupling of tearing fluctuations in the Madison Symmetric Torus
Sarff, J.S.; Almagri, A.F.; Cekic, M.; Den Hartog, D.J.; Fiksel, G.; Hokin, S.A.; Ji, H.; Prager, S.C.; Shen, W.; Stoneking, M.R.; Assadi, S.; Sidikman, K.L.
1992-11-01
Three-wave, nonlinear, tearing mode coupling has been measured in the Madison Symmetric Torus (MST) reversed-field pinch (RFP) [Fusion Technol. 19, 131 (1991)] using bispectral analysis of edge magnetic fluctuations resolved in ``k-space. The strength of nonlinear three-wave interactions satisfying the sum rules m{sub 1} + m{sub 2} = m{sub 3} and n{sub 1} + n{sub 2} = n{sub 3} is measured by the bicoherency. In the RFP, m=l, n{approximately}2R/a (6 for MST) internally resonant modes are linearly unstable and grow to large amplitude. Large values of bicoherency occur for two m=l modes coupled to an m=2 mode and the coupling of intermediate toroidal modes, e.g., n=6 and 7 coupled to n=13. These experimental bispectral features agree with predicted bispectral features derived from MHD computation. However, in the experiment, enhanced coupling occurs in the ``crash`` phase of a sawtooth oscillation concomitant with a broadened mode spectrum suggesting the onset of a nonlinear cascade.
Degenerate parametric oscillation in quantum membrane optomechanics
NASA Astrophysics Data System (ADS)
Benito, Mónica; Sánchez Muñoz, Carlos; Navarrete-Benlloch, Carlos
2016-02-01
The promise of innovative applications has triggered the development of many modern technologies capable of exploiting quantum effects. But in addition to future applications, such quantum technologies have already provided us with the possibility of accessing quantum-mechanical scenarios that seemed unreachable just a few decades ago. With this spirit, in this work we show that modern optomechanical setups are mature enough to implement one of the most elusive models in the field of open system dynamics: degenerate parametric oscillation. Introduced in the eighties and motivated by its alleged implementability in nonlinear optical resonators, it rapidly became a paradigm for the study of dissipative phase transitions whose corresponding spontaneously broken symmetry is discrete. However, it was found that the intrinsic multimode nature of optical cavities makes it impossible to experimentally study the model all the way through its phase transition. In contrast, here we show that this long-awaited model can be implemented in the motion of a mechanical object dispersively coupled to the light contained in a cavity, when the latter is properly driven with multichromatic laser light. We focus on membranes as the mechanical element, showing that the main signatures of the degenerate parametric oscillation model can be studied in state-of-the-art setups, thus opening the possibility of analyzing spontaneous symmetry breaking and enhanced metrology in one of the cleanest dissipative phase transitions. In addition, the ideas put forward in this work would allow for the dissipative preparation of squeezed mechanical states.
Optomechanics in a Millikelvin Environment
NASA Astrophysics Data System (ADS)
Hauer, Bradley; MacDonald, Allison; Popowich, Greg; Kim, Paul; Fredrick, Aron; Rojas, Xavier; Davis, John
2015-03-01
As advances in technology continue to improve the quality and reduce the size of nanofabricated devices, we edge closer and closer to the prospect of observing quantized motion of a mesoscopic mechanical resonator. Measurements of such devices, which consist of billions to trillions of atoms, would provide an excellent test of the scales at which quantum mechanics is applicable. However, due to their relatively large effective masses, these devices must be cooled to mK temperatures to reach their quantum ground state. The field of cavity optomechanics, which has already achieved quantum limited measurement sensitivity, provides a promising avenue for performing such measurements. To this end, we have designed a tapered fiber optomechanical coupling apparatus, with full 3D control and real time imaging of the coupling environment, on the base plate of a dilution refrigerator. This experiment is capable of passively cooling devices to temperatures below 10 mK, at which oscillators with resonance frequencies as low as 150 MHz will be cooled to single phonon occupancy. In this talk, I will present preliminary measurements from this cutting edge system.
Whispering Gallery Mode Optomechanical Resonator
NASA Technical Reports Server (NTRS)
Aveline, David C.; Strekalov, Dmitry V.; Yu, Nan; Yee, Karl Y.
2012-01-01
Great progress has been made in both micromechanical resonators and micro-optical resonators over the past decade, and a new field has recently emerged combining these mechanical and optical systems. In such optomechanical systems, the two resonators are strongly coupled with one influencing the other, and their interaction can yield detectable optical signals that are highly sensitive to the mechanical motion. A particularly high-Q optical system is the whispering gallery mode (WGM) resonator, which has many applications ranging from stable oscillators to inertial sensor devices. There is, however, limited coupling between the optical mode and the resonator s external environment. In order to overcome this limitation, a novel type of optomechanical sensor has been developed, offering great potential for measurements of displacement, acceleration, and mass sensitivity. The proposed hybrid device combines the advantages of all-solid optical WGM resonators with high-quality micro-machined cantilevers. For direct access to the WGM inside the resonator, the idea is to radially cut precise gaps into the perimeter, fabricating a mechanical resonator within the WGM. Also, a strategy to reduce losses has been developed with optimized design of the cantilever geometry and positions of gap surfaces.
Optomechanically induced stochastic resonance and chaos transfer between optical fields
NASA Astrophysics Data System (ADS)
Monifi, Faraz; Zhang, Jing; Özdemir, Şahin Kaya; Peng, Bo; Liu, Yu-Xi; Bo, Fang; Nori, Franco; Yang, Lan
2016-06-01
Chaotic dynamics has been reported in many physical systems and has affected almost every field of science. Chaos involves hypersensitivity to the initial conditions of a system and introduces unpredictability into its output. Thus, it is often unwanted. Interestingly, the very same features make chaos a powerful tool to suppress decoherence, achieve secure communication and replace background noise in stochastic resonance—a counterintuitive concept that a system's ability to transfer information can be coherently amplified by adding noise. Here, we report the first demonstration of chaos-induced stochastic resonance in an optomechanical system, as well as the optomechanically mediated chaos transfer between two optical fields such that they follow the same route to chaos. These results will contribute to the understanding of nonlinear phenomena and chaos in optomechanical systems, and may find applications in the chaotic transfer of information and for improving the detection of otherwise undetectable signals in optomechanical systems.
Cavity optomechanics -- beyond the ground state
NASA Astrophysics Data System (ADS)
Meystre, Pierre
2011-05-01
The coupling of coherent optical systems to micromechanical devices, combined with breakthroughs in nanofabrication and in ultracold science, has opened up the exciting new field of cavity optomechanics. Cooling of the vibrational motion of a broad range on oscillating cantilevers and mirrors near their ground state has been demonstrated, and the ground state of at least one such system has now been reached. Cavity optomechanics offers much promise in addressing fundamental physics questions and in applications such as the detection of feeble forces and fields, or the coherent control of AMO systems and of nanoscale electromechanical devices. However, these applications require taking cavity optomechanics ``beyond the ground state.'' This includes the generation and detection of squeezed and other non-classical states, the transfer of squeezing between electromagnetic fields and motional quadratures, and the development of measurement schemes for the characterization of nanomechanical structures. The talk will present recent ``beyond ground state'' developments in cavity optomechanics. We will show how the magnetic coupling between a mechanical membrane and a BEC - or between a mechanical tuning fork and a nanoscale cantilever - permits to control and monitor the center-of-mass position of the mechanical system, and will comment on the measurement back-action on the membrane motion. We will also discuss of state transfer between optical and microwave fields and micromechanical devices. Work done in collaboration with Dan Goldbaum, Greg Phelps, Keith Schwab, Swati Singh, Steve Steinke, Mehmet Tesgin, and Mukund Vengallatore and supported by ARO, DARPA, NSF, and ONR.
Geometric nonlinear formulation for thermal-rigid-flexible coupling system
NASA Astrophysics Data System (ADS)
Fan, Wei; Liu, Jin-Yang
2013-10-01
This paper develops geometric nonlinear hybrid formulation for flexible multibody system with large deformation considering thermal effect. Different from the conventional formulation, the heat flux is the function of the rotational angle and the elastic deformation, therefore, the coupling among the temperature, the large overall motion and the elastic deformation should be taken into account. Firstly, based on nonlinear strain-displacement relationship, variational dynamic equations and heat conduction equations for a flexible beam are derived by using virtual work approach, and then, Lagrange dynamics equations and heat conduction equations of the first kind of the flexible multibody system are obtained by leading into the vectors of Lagrange multiplier associated with kinematic and temperature constraint equations. This formulation is used to simulate the thermal included hub-beam system. Comparison of the response between the coupled system and the uncoupled system has revealed the thermal chattering phenomenon. Then, the key parameters for stability, including the moment of inertia of the central body, the incident angle, the damping ratio and the response time ratio, are analyzed. This formulation is also used to simulate a three-link system applied with heat flux. Comparison of the results obtained by the proposed formulation with those obtained by the approximate nonlinear model and the linear model shows the significance of considering all the nonlinear terms in the strain in case of large deformation. At last, applicability of the approximate nonlinear model and the linear model are clarified in detail.
Geometric nonlinear formulation for thermal-rigid-flexible coupling system
NASA Astrophysics Data System (ADS)
Fan, Wei; Liu, Jin-Yang
2013-09-01
This paper develops geometric nonlinear hybrid formulation for flexible multibody system with large deformation considering thermal effect. Different from the conventional formulation, the heat flux is the function of the rotational angle and the elastic deformation, therefore, the coupling among the temperature, the large overall motion and the elastic deformation should be taken into account. Firstly, based on nonlinear strain-displacement relationship, variational dynamic equations and heat conduction equations for a flexible beam are derived by using virtual work approach, and then, Lagrange dynamics equations and heat conduction equations of the first kind of the flexible multibody system are obtained by leading into the vectors of Lagrange multiplier associated with kinematic and temperature constraint equations. This formulation is used to simulate the thermal included hub-beam system. Comparison of the response between the coupled system and the uncoupled system has revealed the thermal chattering phenomenon. Then, the key parameters for stability, including the moment of inertia of the central body, the incident angle, the damping ratio and the response time ratio, are analyzed. This formulation is also used to simulate a three-link system applied with heat flux. Comparison of the results obtained by the proposed formulation with those obtained by the approximate nonlinear model and the linear model shows the significance of considering all the nonlinear terms in the strain in case of large deformation. At last, applicability of the approximate nonlinear model and the linear model are clarified in detail.
Nonlinearly coupled dynamics of irregularities in the equatorial electrojet
NASA Astrophysics Data System (ADS)
Atul, J. K.; Sarkar, S.; Singh, S. K.
2016-04-01
Kinetic wave description is used to study the nonlinear influence of background Farley Buneman (FB) modes on the Gradient Drift (GD) modes in the equatorial electrojet ionosphere. The dominant nonlinearity is mediated through the electron flux term in the governing fluid equation which further invokes a turbulent current into the system. Electron dynamics reveals the modification in electron collision frequency and inhomogeneity scale length. It is seen that the propagation and growth rate of GD modes get modified by the background FB modes. Also, a new quasimode gets excited through the quadratic dispersion relation. Physical significance of coupled dynamics between the participating modes is also discussed.
Air-coupled detection of nonlinear Rayleigh surface waves to assess material nonlinearity.
Thiele, Sebastian; Kim, Jin-Yeon; Qu, Jianmin; Jacobs, Laurence J
2014-08-01
This research presents a new technique for nonlinear Rayleigh surface wave measurements that uses a non-contact, air-coupled ultrasonic transducer; this receiver is less dependent on surface conditions than laser-based detection, and is much more accurate and efficient than detection with a contact wedge transducer. A viable experimental setup is presented that enables the robust, non-contact measurement of nonlinear Rayleigh surface waves over a range of propagation distances. The relative nonlinearity parameter is obtained as the slope of the normalized second harmonic amplitudes plotted versus propagation distance. This experimental setup is then used to assess the relative nonlinearity parameters of two aluminum alloy specimens (Al 2024-T351 and Al 7075-T651). These results demonstrate the effectiveness of the proposed technique - the average standard deviation of the normalized second harmonic amplitudes, measured at locations along the propagation path, is below 2%. Experimental validation is provided by a comparison of the ratio of the measured nonlinearity parameters of these specimens with ratios from the absolute nonlinearity parameters for the same materials measured by capacitive detection of nonlinear longitudinal waves. PMID:24836962
Classical and quantum-linearized descriptions of degenerate optomechanical parametric oscillators
NASA Astrophysics Data System (ADS)
Pina-Otey, Sebastian; Jiménez, Fernando; Degenfeld-Schonburg, Peter; Navarrete-Benlloch, Carlos
2016-03-01
Recent advances in the development of modern quantum technologies have opened the possibility of studying the interplay between spontaneous parametric down-conversion and optomechanics, two of the most fundamental nonlinear optical processes. Apart from practical reasons, such a scenario is very interesting from a fundamental point of view, because it allows exploration of the optomechanical interaction in the presence of a strongly quantum-correlated field, the spontaneously down-converted mode. In this work we analyze this problem from two approximate but valuable perspectives: the classical limit and the limit of small quantum fluctuations. We show that, in the presence of optomechanical coupling, the well-known classical phase diagram of the optical problem is modified by the appearance of additional dynamical instabilities. As for the quantum-mechanical description, we prove the ability of the squeezed down-converted field to cool down the mechanical motion not only to thermal but also to squeezed thermal mechanical states, and in a way that can be much less sensitive to the parameters (e.g., detuning of the driving laser) than standard sideband cooling.
NASA Astrophysics Data System (ADS)
Schmidt, M.; Peano, V.; Marquardt, F.
2015-02-01
Recent progress in optomechanical systems may soon allow the realization of optomechanical arrays, i.e. periodic arrangements of interacting optical and vibrational modes. We show that photons and phonons on a honeycomb lattice will produce an optically tunable Dirac-type band structure. Transport in such a system can exhibit transmission through an optically created barrier, similar to Klein tunneling, but with interconversion between light and sound. In addition, edge states at the sample boundaries are dispersive and enable controlled propagation of photon-phonon polaritons.
Nonlinear dynamic analysis of hydrodynamically-coupled stainless steel structures
Zhao, Y.
1996-12-01
Spent nuclear fuel is usually stored temporarily on the site of nuclear power plants. The spent fuel storage racks are nuclear-safety-related stainless steel structures required to be analyzed for seismic loads. When the storage pool is subjected to three-dimensional (3-D) floor seismic excitations, rack modules, stored fuel bundles, adjacent racks and pool walls, and surrounding water are hydrodynamically coupled. Hydrodynamic coupling (HC) significantly affects the dynamic responses of the racks that are free-standing and submerged in water within the pool. A nonlinear time-history dynamic analysis is usually needed to describe the motion behavior of the racks that are both geometrically nonlinear and material nonlinear in nature. The nonlinearities include the friction resistance between the rack supporting legs and the pool floor, and various potential impacts of fuel-rack, rack-rack, and rack-pool wall. The HC induced should be included in the nonlinear dynamic analysis using the added-hydrodynamic-mass concept based on potential theory per the US Nuclear Regulatory Commission (USNRC) acceptance criteria. To this end, a finite element analysis constitutes a feasible and effective tool. However, most people perform somewhat simplified 1-D, or 2-D, or 3-D single rack and 2-D multiple rack analyses. These analyses are incomplete because a 3-D single rack model behaves quite differently from a 2-D mode. Furthermore, a 3-D whole pool multi-rack model behaves differently than a 3-D single rack model, especially when the strong HC effects are unsymmetrical. In this paper 3-D nonlinear dynamic time-history analyses were performed in a more quantitative manner using sophisticated finite element models developed for a single rack as well as all twelve racks in the whole-pool. Typical response results due to different HC effects are determined and discussed.
Nonlinear waves in coherently coupled Bose-Einstein condensates
NASA Astrophysics Data System (ADS)
Congy, T.; Kamchatnov, A. M.; Pavloff, N.
2016-04-01
We consider a quasi-one-dimensional two-component Bose-Einstein condensate subject to a coherent coupling between its components, such as realized in spin-orbit coupled condensates. We study how nonlinearity modifies the dynamics of the elementary excitations. The spectrum has two branches, which are affected in different ways. The upper branch experiences a modulational instability, which is stabilized by a long-wave-short-wave resonance with the lower branch. The lower branch is stable. In the limit of weak nonlinearity and small dispersion it is described by a Korteweg-de Vries equation or by the Gardner equation, depending on the value of the parameters of the system.
Semiclassical nonlinear response functions for coupled anharmonic vibrations
Gruenbaum, Scott M.; Loring, Roger F.
2009-11-28
Observables in linear and nonlinear infrared spectroscopy may be computed from vibrational response functions describing nuclear dynamics on a single electronic surface. We demonstrate that the Herman-Kluk (HK) semiclassical approximation to the quantum propagator yields an accurate representation of quantum coherence effects in linear and nonlinear response functions for coupled anharmonic oscillators. A considerable numerical price is paid for this accuracy; the calculation requires a multidimensional integral over a highly oscillatory integrand that also grows without bound as a function of evolution times. The interference among classical trajectories in the HK approximation produces quantization of good action variables. By treating this interference analytically, we develop a mean-trajectory (MT) approximation that requires only the propagation of classical trajectories linked by transitions in action. The MT approximation accurately reproduces coherence effects in response functions of coupled anharmonic oscillators in a regime in which the observables are strongly influenced by these interactions among vibrations.
Multistable internal resonance in electroelastic crystals with nonlinearly coupled modes
NASA Astrophysics Data System (ADS)
Kirkendall, Christopher R.; Kwon, Jae W.
2016-03-01
Nonlinear modal interactions have recently become the focus of intense research in micro- and nanoscale resonators for their use to improve oscillator performance and probe the frontiers of fundamental physics. However, our understanding of modal coupling is largely restricted to clamped-clamped beams, and lacking in systems with both geometric and material nonlinearities. Here we report multistable energy transfer between internally resonant modes of an electroelastic crystal plate and use a mixed analytical-numerical approach to provide new insight into these complex interactions. Our results reveal a rich bifurcation structure marked by nested regions of multistability. Even the simple case of two coupled modes generates a host of topologically distinct dynamics over the parameter space, ranging from the usual Duffing bistability to complex multistable behaviour and quasiperiodic motion.
Multistable internal resonance in electroelastic crystals with nonlinearly coupled modes
Kirkendall, Christopher R.; Kwon, Jae W.
2016-01-01
Nonlinear modal interactions have recently become the focus of intense research in micro- and nanoscale resonators for their use to improve oscillator performance and probe the frontiers of fundamental physics. However, our understanding of modal coupling is largely restricted to clamped-clamped beams, and lacking in systems with both geometric and material nonlinearities. Here we report multistable energy transfer between internally resonant modes of an electroelastic crystal plate and use a mixed analytical-numerical approach to provide new insight into these complex interactions. Our results reveal a rich bifurcation structure marked by nested regions of multistability. Even the simple case of two coupled modes generates a host of topologically distinct dynamics over the parameter space, ranging from the usual Duffing bistability to complex multistable behaviour and quasiperiodic motion. PMID:26961749
Resonant self-pulsations in coupled nonlinear microcavities
Grigoriev, Victor; Biancalana, Fabio
2011-04-15
A different point of view on the phenomenon of self-pulsations is presented, which shows that they are a balanced state formed by two counteracting processes: beating of modes and bistable switching. A structure based on two coupled nonlinear microcavities provides a generic example of a system with enhanced ability to support this phenomenon. The specific design of such a structure in the form of multilayered media is proposed, and the coupled-mode theory is applied to describe its dynamical properties. It is emphasized that the frequency of self-pulsations is related to the frequency splitting between resonant modes and can be adjusted over a broad range.
Controllable chaos in hybrid electro-optomechanical systems.
Wang, Mei; Lü, Xin-You; Ma, Jin-Yong; Xiong, Hao; Si, Liu-Gang; Wu, Ying
2016-01-01
We investigate the nonlinear dynamics of a hybrid electro-optomechanical system (EOMS) that allows us to realize the controllable opto-mechanical nonlinearity by driving the microwave LC resonator with a tunable electric field. A controllable optical chaos is realized even without changing the optical pumping. The threshold and lifetime of the chaos could be optimized by adjusting the strength, frequency, or phase of the electric field. This study provides a method of manipulating optical chaos with an electric field. It may offer the prospect of exploring the controllable chaos in on-chip optoelectronic devices and its applications in secret communication. PMID:26948505
Controllable chaos in hybrid electro-optomechanical systems
NASA Astrophysics Data System (ADS)
Wang, Mei; Lü, Xin-You; Ma, Jin-Yong; Xiong, Hao; Si, Liu-Gang; Wu, Ying
2016-03-01
We investigate the nonlinear dynamics of a hybrid electro-optomechanical system (EOMS) that allows us to realize the controllable opto-mechanical nonlinearity by driving the microwave LC resonator with a tunable electric field. A controllable optical chaos is realized even without changing the optical pumping. The threshold and lifetime of the chaos could be optimized by adjusting the strength, frequency, or phase of the electric field. This study provides a method of manipulating optical chaos with an electric field. It may offer the prospect of exploring the controllable chaos in on-chip optoelectronic devices and its applications in secret communication.
Controllable chaos in hybrid electro-optomechanical systems
Wang, Mei; Lü, Xin-You; Ma, Jin-Yong; Xiong, Hao; Si, Liu-Gang; Wu, Ying
2016-01-01
We investigate the nonlinear dynamics of a hybrid electro-optomechanical system (EOMS) that allows us to realize the controllable opto-mechanical nonlinearity by driving the microwave LC resonator with a tunable electric field. A controllable optical chaos is realized even without changing the optical pumping. The threshold and lifetime of the chaos could be optimized by adjusting the strength, frequency, or phase of the electric field. This study provides a method of manipulating optical chaos with an electric field. It may offer the prospect of exploring the controllable chaos in on-chip optoelectronic devices and its applications in secret communication. PMID:26948505
Nonlinear source–filter coupling in phonation: Vocal exercises
Titze, Ingo; Riede, Tobias; Popolo, Peter
2008-01-01
Nonlinear source–filter coupling has been demonstrated in computer simulations, in excised larynx experiments, and in physical models, but not in a consistent and unequivocal way in natural human phonations. Eighteen subjects (nine adult males and nine adult females) performed three vocal exercises that represented a combination of various fundamental frequency and formant glides. The goal of this study was to pinpoint the proportion of source instabilities that are due to nonlinear source–tract coupling. It was hypothesized that vocal fold vibration is maximally destabilized when F0 crosses F1, where the acoustic load changes dramatically. A companion paper provides the theoretical underpinnings. Expected manifestations of a source–filter interaction were sudden frequency jumps, subharmonic generation, or chaotic vocal fold vibrations that coincide with F0–F1 crossovers. Results indicated that the bifurcations occur more often in phonations with F0–F1 crossovers, suggesting that nonlinear source–filter coupling is partly responsible for source instabilities. Furthermore it was observed that male subjects show more bifurcations in phonations with F0–F1 crossovers, presumably because in normal speech they are less likely to encounter these crossovers as much as females and hence have less practice in suppressing unwanted instabilities. PMID:18396999
Nonlinear source-filter coupling in phonation: vocal exercises.
Titze, Ingo; Riede, Tobias; Popolo, Peter
2008-04-01
Nonlinear source-filter coupling has been demonstrated in computer simulations, in excised larynx experiments, and in physical models, but not in a consistent and unequivocal way in natural human phonations. Eighteen subjects (nine adult males and nine adult females) performed three vocal exercises that represented a combination of various fundamental frequency and formant glides. The goal of this study was to pinpoint the proportion of source instabilities that are due to nonlinear source-tract coupling. It was hypothesized that vocal fold vibration is maximally destabilized when F(0) crosses F(1), where the acoustic load changes dramatically. A companion paper provides the theoretical underpinnings. Expected manifestations of a source-filter interaction were sudden frequency jumps, subharmonic generation, or chaotic vocal fold vibrations that coincide with F(0)-F(1) crossovers. Results indicated that the bifurcations occur more often in phonations with F(0)-F(1) crossovers, suggesting that nonlinear source-filter coupling is partly responsible for source instabilities. Furthermore it was observed that male subjects show more bifurcations in phonations with F(0)-F(1) crossovers, presumably because in normal speech they are less likely to encounter these crossovers as much as females and hence have less practice in suppressing unwanted instabilities. PMID:18396999
Nonlinear mode coupling and vibrational energy transfer in Yukawa clusters
NASA Astrophysics Data System (ADS)
Qiao, Ke; Kong, Jie; Matthews, Lorin; Hyde, Truell
2015-11-01
Nonlinear mode coupling and the subsequent vibrational energy transfer that results is an important topic in chemical physics research, ranging from small molecules consisting of several atoms to macromolecules such as those found in proteins and DNA. Nonlinear mode coupling is recognized as the mechanism leading to ergodicity, which is a foundational tenet of statistical mechanics. Over the past two decades, Yukawa systems of particles such as those found in complex plasma, have been shown to be an effective model across a large number of physical systems. In this research, nonlinear mode coupling in Yukawa clusters consisting of 3-10 particles is examined via numerical simulation of the vibrational energy transfer between modes starting from an initial excited state. The relationship between the energy transfer process and the internal resonance between modes having a specified frequency ratio and the temporal evolution of the system to a state of equal energy across all modes, i.e., the state of ergodicity, will be discussed. Support from the NSF and the DOE (award numbers PHY-1262031 and PHY-1414523) is gratefully acknowledged.
Design of tunable GHz-frequency optomechanical crystal resonators.
Pfeifer, Hannes; Paraïso, Taofiq; Zang, Leyun; Painter, Oskar
2016-05-30
We present a silicon optomechanical nanobeam design with a dynamically tunable acoustic mode at 10.2 GHz. The resonance frequency can be shifted by 90 kHz/V^{2} with an on-chip capacitor that was optimized to exert forces up to 1 µN at 10 V operation voltage. Optical resonance frequencies around 190 THz with Q-factors up to 2.2 × 10^{6} place the structure in the well-resolved sideband regime with vacuum optomechanical coupling rates up to g_{0}/2π = 353 kHz. Tuning can be used, for instance, to overcome variation in the device-to-device acoustic resonance frequency due to fabrication errors, paving the way for optomechanical circuits consisting of arrays of optomechanical cavities. PMID:27410069
Sensitivity and performance of cavity optomechanical field sensors
NASA Astrophysics Data System (ADS)
Forstner, Stefan; Knittel, Joachim; Sheridan, Eoin; Swaim, Jon D.; Rubinsztein-Dunlop, Halina; Bowen, Warwick P.
2012-09-01
This article describes in detail a technique for modeling cavity optomechanical field sensors. A magnetic or electric field induces a spatially varying stress across the sensor, which then induces a force on mechanical eigenmodes of the system. The force on each oscillator can then be determined from an overlap integral between magnetostrictive stress and the corresponding eigenmode, with the optomechanical coupling strength determining the ultimate resolution with which this force can be detected. Furthermore, an optomechanical magnetic field sensor is compared to other magnetic field sensors in terms of sensitivity and potential for miniaturization. It is shown that an optomechanical sensor can potentially outperform state-of-the-art magnetometers of similar size, in particular other sensors based on a magnetostrictive mechanism.
Fiber-Cavity Optomechanics with Superfluid Helium
NASA Astrophysics Data System (ADS)
Flowers-Jacobs, Nathan E.; Kashkanova, Anna D.; Shkarin, Alexey B.; Hoch, Scott W.; Deutsch, Christian; Reichel, Jakob; Harris, Jack G. E.
2014-03-01
In a typical optomechanical device, the resonance frequency of a cavity is coupled to mechanical motion through the radiation pressure force. To date, experimental cavities have predominately coupled to a resonant mechanical mode of a solid structure, often a lithographically-defined beam or membrane. We will describe our progress towards realizing an optomechanical device in which an optical fiber-cavity couples to the acoustic modes of superfluid helium. In this system, the optical modes and the acoustic modes of the superfluid are co-located between the mirrored ends of two fiber optic cables. Changes in the density of the superfluid change the effective length of the cavity which results in a standard, linear optomechanical coupling between the 300 MHz acoustic resonances and the 200 THz optical resonances. This type of device is motivated by the self-aligning nature of the acoustic and optical modes (which eases the difficulties of operating at cryogenic temperatures) and by the low optical and mechanical losses of superfluid helium. Although we expect the mechanical quality factor to be limited by acoustic radiation into the glass fiber, we will describe a proposal to realize a dual-band Bragg mirror to confine the optical and acoustic modes more efficiently. Supported by NSF Grant #1106110, ARO Grant #W911NF-13-1-0104, and the DARPA/MTO ORCHID program through a grant from AFOSR.
Spin-based optomechanics with carbon nanotubes.
Li, Jin-Jin; Zhu, Ka-Di
2012-01-01
A simple scheme for determination of spin-orbit coupling strength in spinbased optomechanics with carbon nanotubes is introduced, under the control of a strong pump field and a weak signal field. The physical mechanism comes from the phonon induced transparency (PIT), by relying on the coherent coupling of electron spin to vibrational motion of the nanotube, which is analogous to electromagnetically induced transparency (EIT) effect in atom systems. Based on this spin-nanotube optomechanical system, we also conceptually design a single photon router and a quantum microwave transistor, with ultralow pump power (~ pW) and tunable switching time, which should provide a unique platform for the study of spin-based microwave quantum optics and quantum information processing. PMID:23198093
Spin-based Optomechanics with Carbon Nanotubes
Li, Jin-Jin; Zhu, Ka-Di
2012-01-01
A simple scheme for determination of spin-orbit coupling strength in spinbased optomechanics with carbon nanotubes is introduced, under the control of a strong pump field and a weak signal field. The physical mechanism comes from the phonon induced transparency (PIT), by relying on the coherent coupling of electron spin to vibrational motion of the nanotube, which is analogous to electromagnetically induced transparency (EIT) effect in atom systems. Based on this spin-nanotube optomechanical system, we also conceptually design a single photon router and a quantum microwave transistor, with ultralow pump power (~ pW) and tunable switching time, which should provide a unique platform for the study of spin-based microwave quantum optics and quantum information processing. PMID:23198093
Silicon optomechanical crystal resonator at millikelvin temperatures
NASA Astrophysics Data System (ADS)
Meenehan, Seán M.; Cohen, Justin D.; Gröblacher, Simon; Hill, Jeff T.; Safavi-Naeini, Amir H.; Aspelmeyer, Markus; Painter, Oskar
2014-07-01
Optical measurements of a nanoscale silicon optomechanical crystal cavity with a mechanical resonance frequency of 3.6 GHz are performed at subkelvin temperatures. We infer optical-absorption-induced heating and damping of the mechanical resonator from measurements of phonon occupancy and motional sideband asymmetry. At the lowest probe power and lowest fridge temperature (Tf=10 mK), the localized mechanical resonance is found to couple at a rate of γi/2π=400 Hz (Qm=9×106) to a thermal bath of temperature Tb≈270 mK. These measurements indicate that silicon optomechanical crystals cooled to millikelvin temperatures should be suitable for a variety of experiments involving coherent coupling between photons and phonons at the single quanta level.
Spatiotemporal mode structure of nonlinearly coupled drift wave modes
Brandt, Christian; Grulke, Olaf; Klinger, Thomas; Negrete, Jose Jr.; Bousselin, Guillaume; Brochard, Frederic; Bonhomme, Gerard; Oldenbuerger, Stella
2011-11-15
This paper presents full cross-section measurements of drift waves in the linear magnetized plasma of the Mirabelle device. Drift wave modes are studied in regimes of weakly developed turbulence. The drift wave modes develop azimuthal space-time structures of plasma density, plasma potential, and visible light fluctuations. A fast camera diagnostic is used to record visible light fluctuations of the plasma column in an azimuthal cross section with a temporal resolution of 10 {mu}s corresponding approximately to 10% of the typical drift wave period. Mode coupling and drift wave dispersion are studied by spatiotemporal Fourier decomposition of the camera frames. The observed coupling between modes is compared to calculations of nonlinearly coupled oscillators described by the Kuramoto model.
Higher-order spectra for identification of nonlinear modal coupling
NASA Astrophysics Data System (ADS)
Hickey, Daryl; Worden, Keith; Platten, Michael F.; Wright, Jan R.; Cooper, Jonathan E.
2009-05-01
Over the past four decades considerable work has been done in the area of power spectrum estimation. The information contained within the power spectrum relates to a signal's autocorrelation or 'second-order statistics'. The power spectrum provides a complete statistical description of a Gaussian process; however, a problem with this information is that it is phase blind. This problem is addressed if one turns to a system's frequency response function (FRF). The FRF graphs the magnitude and phase of the frequency response of a system; in order to do this it requires information regarding the frequency content of the input and output signals. Situations arise in science and engineering whereby signal analysts are required to look beyond second-order statistics and analyse a signal's higher-order statistics (HOS). HOS or spectra give information on a signal's deviation from Gaussianity and consequently are a good indicator function for the presence of nonlinearity within a system. One of the main problems in nonlinear system identification is that of high modal density. Many modelling schemes involve making some expansion of the nonlinear restoring force in terms of polynomial or other basis terms. If more than one degree-of-freedom is involved this becomes a multivariate problem and the number of candidate terms in the expansion grows explosively with the order of nonlinearity and the number of degrees-of-freedom. This paper attempts to use HOS to detect and qualify nonlinear behaviour for a number of symmetrical and asymmetrical systems over a range of degrees-of-freedom. In doing so the paper also attempts to show that HOS are a more sensitive tool than the FRF in detecting nonlinearity. Furthermore, the object of this paper is to try and identify which modes couple in a nonlinear manner in order to reduce the number of candidate coupling terms, for a model, as much as possible. The bispectrum method has previously been applied to simple low-DOF systems with high
Jean C. Ragusa; Vijay Mahadevan; Vincent A. Mousseau
2009-05-01
High-fidelity modeling of nuclear reactors requires the solution of a nonlinear coupled multi-physics stiff problem with widely varying time and length scales that need to be resolved correctly. A numerical method that converges the implicit nonlinear terms to a small tolerance is often referred to as nonlinearly consistent (or tightly coupled). This nonlinear consistency is still lacking in the vast majority of coupling techniques today. We present a tightly coupled multiphysics framework that tackles this issue and present code-verification and convergence analyses in space and time for several models of nonlinear coupled physics.
Coupled nonlinear oscillation and stability evolution of viscoelastic dielectric elastomers.
Zhang, Junshi; Chen, Hualing; Li, Bo; McCoul, David; Pei, Qibing
2015-10-14
This article describes the development of an analytical model to study the coupled nonlinear oscillation and stability evolution of viscoelastic dielectric elastomers (DEs) under non-equibiaxial tensile forces by utilizing the method of virtual work. Numerically calculated results are employed to predict this nonlinear dynamic behavior. The resonant frequency (where the amplitude-frequency response curve peaks) and the amplitude-frequency response of the deformation in both in-plane directions are tuned by varying the values of tensile force. The oscillation response in the two in-plane directions exhibits strong nonlinearity and coupling with each other, and is tuned by the changing tensile forces under a specific excitation frequency. By varying the values of tensile forces, the dynamic viscoelastic creep in a certain in-plane direction can be eliminated. Phase diagrams and Poincaré maps under several values of tensile forces are utilized to study the stability evolution of the DE system under non-equibiaxial tensile forces. PMID:26287474
Optomechanical engineering education at University of Arizona
NASA Astrophysics Data System (ADS)
Burge, James H.; Parks, Robert
2009-08-01
The College of Optical Sciences at University of Arizona has established excellent programs for training BS, MS, and Ph.D. students in optical sciences and engineering. Research activities at the University of Arizona have also been closely coupled to developments in the field of optomechanical engineering. In response to request from the optics industry, we have recently expanded the educational opportunities for BS and MS students to follow engineering curricula that provide the right mix of optics and mechanical engineering.
Phonon Cooling by an Optomechanical Heat Pump
NASA Astrophysics Data System (ADS)
Dong, Ying; Bariani, F.; Meystre, P.
2015-11-01
We propose and analyze theoretically a cavity optomechanical analog of a heat pump that uses a polariton fluid to cool mechanical modes coupled to a single precooled phonon mode via external modulation of the substrate of the mechanical resonator. This approach permits us to cool phonon modes of arbitrary frequencies not limited by the cavity-optical field detuning deep into the quantum regime from room temperature.
A nonlinear generalized continuum approach for electro-mechanical coupling
NASA Astrophysics Data System (ADS)
Skatulla, S.; Arockiarajan, A.; Sansour, C.
2008-07-01
Electro-active polymers (EAP) are "smart materials" whose mechanical properties may be changed significantly by the application of electric field. Hence, these materials can serve as actuators in electro-mechanical systems, artificial muscles, etc. In this paper, we provide a generalized continuum framework basis for the characterization of the nonlinear electroelastic properties of these materials. This approach introduces new strain and stress measures which lead to the formulation of a corresponding generalized variational principle. The theory is then completed by Dirichlet boundary conditions for the displacement field and the electric potential and then derivatives normal to the boundary. The basic idea behind this generalized continuum framework is the consideration of a micro- and a macro-space which together span the generalized space. All quantities including the constitutive law for the electro-mechanically coupled nonlinear hyperelasticity are defined in the generalized space. Numerical examples are presented to demonstrate the numerical accuracy of the implemented formulation using the mesh free method.
Two coupled nonlinear cavities in a driven-dissipative environment
NASA Astrophysics Data System (ADS)
Cao, Bin; Mahmud, Khan; Hafezi, Mohammad
We investigate two coupled nonlinear cavities that are driven coherently in a dissipative environment. This is the simplest setting containing a good number of features of an array of coupled cavity quantum simulator with Kerr nonlinearity which gives rise to many strongly correlated phases. We find analytical solution for the steady state using the generalized P representation and expressing the master equation in the form of Fokker-Planck equation. A comparison shows a good match of the analytical and numerical solutions across different regimes. We investigate the quantum correlations in the steady state by solving the full master equation numerically, analyzing its second-order coherence, entanglment entropy and Liouvillian gap as a function of drive and detuning. This gives us insights into the nature of bistability and how the tunneling-induced bistability emerges in coupled cavities when going beyond a single cavity. We can understand much of the semiclassical physics in terms of the underlying phase space dynamics of a driven and damped classical pendulum. Furthermore, in the semiclassical analysis, we find steady state solutions with different number density in the two wells that can be considered an analog of double well self-trapped states.
Hopf bifurcation with dihedral group symmetry - Coupled nonlinear oscillators
NASA Technical Reports Server (NTRS)
Golubitsky, Martin; Stewart, Ian
1986-01-01
The theory of Hopf bifurcation with symmetry developed by Golubitsky and Stewart (1985) is applied to systems of ODEs having the symmetries of a regular polygon, that is, whose symmetry group is dihedral. The existence and stability of symmetry-breaking branches of periodic solutions are considered. In particular, these results are applied to a general system of n nonlinear oscillators coupled symmetrically in a ring, and the generic oscillation patterns are described. It is found that the symmetry can force some oscillators to have twice the frequency of others. The case of four oscillators has exceptional features.
Observation of chaotic dynamics of coupled nonlinear oscillators
NASA Astrophysics Data System (ADS)
van Buskirk, R.; Jeffries, C.
1985-05-01
Experimental data are employed as bases for theoretically modelling the behavior of a finite number of driven nonlinear coupled oscillators. Attention is focused on Si p-n junction resonators exposed to an external inductance. A junction oscillator displays period doubling, Hopf figuracions to quasi-periodicity, entrainment horns and breakup of the invariant torus. Calculated and measured data are compared, with favorable results, by means of Poincare' sections, bifurcation diagrams and parameter phase space diagrams for the drive voltage and frequency. Fractal dimensions 2.03 and 2.33 are expressed in Poincare' sections to illustrate the behavior of single and dual coupled resonators which experience a breakup of the strange attractor.
Multipulses of Nonlinearly Coupled Schrödinger Equations
NASA Astrophysics Data System (ADS)
Yew, Alice C.
2001-06-01
The capacity of coupled nonlinear Schrödinger (NLS) equations to support multipulse solutions (multibump solitary-waves) is investigated. A detailed analysis is undertaken for a system of quadratically coupled equations that describe the phenomena of second harmonic generation and parametric wave interaction in non-centrosymmetric optical materials. Utilising the framework of homoclinic bifurcation theory, and employing a Lyapunov-Schmidt reduction method developed by Hale, Lin, and Sandstede, a novel mechanism for the generation of multipulses is identified, which arises from a resonant semi-simple eigenvalue configuration of the linearised steady-state equations. Conditions for the existence of multipulses, as well as a description of their geometry, are derived from the analysis.
Integrable pair-transition-coupled nonlinear Schrödinger equations
NASA Astrophysics Data System (ADS)
Ling, Liming; Zhao, Li-Chen
2015-08-01
We study integrable coupled nonlinear Schrödinger equations with pair particle transition between components. Based on exact solutions of the coupled model with attractive or repulsive interaction, we predict that some new dynamics of nonlinear excitations can exist, such as the striking transition dynamics of breathers, new excitation patterns for rogue waves, topological kink excitations, and other new stable excitation structures. In particular, we find that nonlinear wave solutions of this coupled system can be written as a linear superposition of solutions for the simplest scalar nonlinear Schrödinger equation. Possibilities to observe them are discussed in a cigar-shaped Bose-Einstein condensate with two hyperfine states. The results would enrich our knowledge on nonlinear excitations in many coupled nonlinear systems with transition coupling effects, such as multimode nonlinear fibers, coupled waveguides, and a multicomponent Bose-Einstein condensate system.
Integrable pair-transition-coupled nonlinear Schrödinger equations.
Ling, Liming; Zhao, Li-Chen
2015-08-01
We study integrable coupled nonlinear Schrödinger equations with pair particle transition between components. Based on exact solutions of the coupled model with attractive or repulsive interaction, we predict that some new dynamics of nonlinear excitations can exist, such as the striking transition dynamics of breathers, new excitation patterns for rogue waves, topological kink excitations, and other new stable excitation structures. In particular, we find that nonlinear wave solutions of this coupled system can be written as a linear superposition of solutions for the simplest scalar nonlinear Schrödinger equation. Possibilities to observe them are discussed in a cigar-shaped Bose-Einstein condensate with two hyperfine states. The results would enrich our knowledge on nonlinear excitations in many coupled nonlinear systems with transition coupling effects, such as multimode nonlinear fibers, coupled waveguides, and a multicomponent Bose-Einstein condensate system. PMID:26382492
Out-of-unison resonance in weakly nonlinear coupled oscillators
Hill, T. L.; Cammarano, A.; Neild, S. A.; Wagg, D. J.
2015-01-01
Resonance is an important phenomenon in vibrating systems and, in systems of nonlinear coupled oscillators, resonant interactions can occur between constituent parts of the system. In this paper, out-of-unison resonance is defined as a solution in which components of the response are 90° out-of-phase, in contrast to the in-unison responses that are normally considered. A well-known physical example of this is whirling, which can occur in a taut cable. Here, we use a normal form technique to obtain time-independent functions known as backbone curves. Considering a model of a cable, this approach is used to identify out-of-unison resonance and it is demonstrated that this corresponds to whirling. We then show how out-of-unison resonance can occur in other two degree-of-freedom nonlinear oscillators. Specifically, an in-line oscillator consisting of two masses connected by nonlinear springs—a type of system where out-of-unison resonance has not previously been identified—is shown to have specific parameter regions where out-of-unison resonance can occur. Finally, we demonstrate how the backbone curve analysis can be used to predict the responses of forced systems. PMID:25568619
The optomechanical instability in the quantum regime
NASA Astrophysics Data System (ADS)
Ludwig, Max; Kubala, Björn; Marquardt, Florian
2008-09-01
We consider a generic optomechanical system, consisting of a driven optical cavity and a movable mirror attached to a cantilever. Systems of this kind (and analogues) have been realized in many recent experiments. It is well known that these systems can exhibit an instability towards a regime where the cantilever settles into self-sustained oscillations. In this paper, we briefly review the classical theory of the optomechanical instability, and then discuss the features arising in the quantum regime. We solve numerically a full quantum master equation for the coupled system, and use it to analyze the photon number, the cantilever's mechanical energy, the phonon probability distribution and the mechanical Wigner density, as a function of experimentally accessible control parameters. When a suitable dimensionless 'quantum parameter' is sent to zero, the results of the quantum mechanical model converge towards the classical predictions. We discuss this quantum-to-classical transition in some detail.
Multimode circuit optomechanics near the quantum limit
Massel, Francesco; Cho, Sung Un; Pirkkalainen, Juha-Matti; Hakonen, Pertti J.; Heikkilä, Tero T.; Sillanpää, Mika A.
2012-01-01
The coupling of distinct systems underlies nearly all physical phenomena. A basic instance is that of interacting harmonic oscillators, giving rise to, for example, the phonon eigenmodes in a lattice. Of particular importance are the interactions in hybrid quantum systems, which can combine the benefits of each part in quantum technologies. Here we investigate a hybrid optomechanical system having three degrees of freedom, consisting of a microwave cavity and two micromechanical beams with closely spaced frequencies around 32 MHz and no direct interaction. We record the first evidence of tripartite optomechanical mixing, implying that the eigenmodes are combinations of one photonic and two phononic modes. We identify an asymmetric dark mode having a long lifetime. Simultaneously, we operate the nearly macroscopic mechanical modes close to the motional quantum ground state, down to 1.8 thermal quanta, achieved by back-action cooling. These results constitute an important advance towards engineering of entangled motional states. PMID:22871806
Reconfigurable long-range phonon dynamics in optomechanical arrays.
Xuereb, André; Genes, Claudiu; Pupillo, Guido; Paternostro, Mauro; Dantan, Aurélien
2014-04-01
We investigate periodic optomechanical arrays as reconfigurable platforms for engineering the coupling between multiple mechanical and electromagnetic modes and for exploring many-body phonon dynamics. Exploiting structural resonances in the coupling between light fields and collective motional modes of the array, we show that tunable effective long-range interactions between mechanical modes can be achieved. This paves the way towards the implementation of controlled phononic walks and heat transfer on densely connected graphs as well as the coherent transfer of excitations between distant elements of optomechanical arrays. PMID:24745417
Coupled nonlinear aeroelasticity and flight dynamics of fully flexible aircraft
NASA Astrophysics Data System (ADS)
Su, Weihua
This dissertation introduces an approach to effectively model and analyze the coupled nonlinear aeroelasticity and flight dynamics of highly flexible aircraft. A reduced-order, nonlinear, strain-based finite element framework is used, which is capable of assessing the fundamental impact of structural nonlinear effects in preliminary vehicle design and control synthesis. The cross-sectional stiffness and inertia properties of the wings are calculated along the wing span, and then incorporated into the one-dimensional nonlinear beam formulation. Finite-state unsteady subsonic aerodynamics is used to compute airloads along lifting surfaces. Flight dynamic equations are then introduced to complete the aeroelastic/flight dynamic system equations of motion. Instead of merely considering the flexibility of the wings, the current work allows all members of the vehicle to be flexible. Due to their characteristics of being slender structures, the wings, tail, and fuselage of highly flexible aircraft can be modeled as beams undergoing three dimensional displacements and rotations. New kinematic relationships are developed to handle the split beam systems, such that fully flexible vehicles can be effectively modeled within the existing framework. Different aircraft configurations are modeled and studied, including Single-Wing, Joined-Wing, Blended-Wing-Body, and Flying-Wing configurations. The Lagrange Multiplier Method is applied to model the nodal displacement constraints at the joint locations. Based on the proposed models, roll response and stability studies are conducted on fully flexible and rigidized models. The impacts of the flexibility of different vehicle members on flutter with rigid body motion constraints, flutter in free flight condition, and roll maneuver performance are presented. Also, the static stability of the compressive member of the Joined-Wing configuration is studied. A spatially-distributed discrete gust model is incorporated into the time simulation
From cavity QED with quantum gases to optomechanics
Ritsch, Helmut
2011-10-03
We study the nonlinear coupled dynamics of ultra-cold quantum gases trapped in the light field of high Q optical resonators. In the very low temperature limit the quantum nature of both, light and ultra-cold matter play equally important roles. Using the dynamically generated entanglement and properly designed measurements procedures of the light field allows controlled preparation of many-body atomic states as e.g. atom number squeezed states or Schroedinger cat states. If one traps the particles inside the optical cavity, one can create a optical potential, which is a quantized and a dynamical variable itself. In addition it mediates controllable long range interactions. The self-consistent solution for light and particles the includes new classes of quantum many-body states as super-solid states and polaron like excitations. In the deep trap limit the collective coupling of the particles and the field can be tailored to reproduce a wide range of optomechanic Hamiltonians with linear, quadratic or even higher order couplings in an environment very close to zero temperature.
Phononic Phase Conjugation in an Optomechanical System
NASA Astrophysics Data System (ADS)
Buchmann, Lukas; Wright, Ewan; Meystre, Pierre
2013-05-01
We study theoretically the phase conjugation of a phononic field in an optomechanical system with two mechanical modes coupled to a common optical field. Phase conjugation becomes the dominant process for an appropriate choice of driving field parameters, and he effective coupling coefficients between phonon modes can result in amplification and entanglement, phase-conjugation or a mixture thereof. We discuss surprising consequences of mechanical phase-conjugation that could lead to the preparation of mechanical states with negative temperature, the improvement of quantum memories and the study of the quantum-classical transition. Supported by DARPA ORCHID program.
Parity-time-symmetry enhanced optomechanically-induced-transparency
NASA Astrophysics Data System (ADS)
Li, Wenlin; Jiang, Yunfeng; Li, Chong; Song, Heshan
2016-08-01
We propose and analyze a scheme to enhance optomechanically-induced-transparency (OMIT) based on parity-time-symmetric optomechanical system. Our results predict that an OMIT window which does not exist originally can appear in weak optomechanical coupling and driving system via coupling an auxiliary active cavity with optical gain. This phenomenon is quite different from these reported in previous works in which the gain is considered just to damage OMIT phenomenon even leads to electromagnetically induced absorption or inverted-OMIT. Such enhanced OMIT effects are ascribed to the additional gain which can increase photon number in cavity without reducing effective decay. We also discuss the scheme feasibility by analyzing recent experiment parameters. Our work provide a promising platform for the coherent manipulation and slow light operation, which has potential applications for quantum information processing and quantum optical device.
Parity-time-symmetry enhanced optomechanically-induced-transparency
Li, Wenlin; Jiang, Yunfeng; Li, Chong; Song, Heshan
2016-01-01
We propose and analyze a scheme to enhance optomechanically-induced-transparency (OMIT) based on parity-time-symmetric optomechanical system. Our results predict that an OMIT window which does not exist originally can appear in weak optomechanical coupling and driving system via coupling an auxiliary active cavity with optical gain. This phenomenon is quite different from these reported in previous works in which the gain is considered just to damage OMIT phenomenon even leads to electromagnetically induced absorption or inverted-OMIT. Such enhanced OMIT effects are ascribed to the additional gain which can increase photon number in cavity without reducing effective decay. We also discuss the scheme feasibility by analyzing recent experiment parameters. Our work provide a promising platform for the coherent manipulation and slow light operation, which has potential applications for quantum information processing and quantum optical device. PMID:27489193
Parity-time-symmetry enhanced optomechanically-induced-transparency.
Li, Wenlin; Jiang, Yunfeng; Li, Chong; Song, Heshan
2016-01-01
We propose and analyze a scheme to enhance optomechanically-induced-transparency (OMIT) based on parity-time-symmetric optomechanical system. Our results predict that an OMIT window which does not exist originally can appear in weak optomechanical coupling and driving system via coupling an auxiliary active cavity with optical gain. This phenomenon is quite different from these reported in previous works in which the gain is considered just to damage OMIT phenomenon even leads to electromagnetically induced absorption or inverted-OMIT. Such enhanced OMIT effects are ascribed to the additional gain which can increase photon number in cavity without reducing effective decay. We also discuss the scheme feasibility by analyzing recent experiment parameters. Our work provide a promising platform for the coherent manipulation and slow light operation, which has potential applications for quantum information processing and quantum optical device. PMID:27489193
A microelectromechanically controlled cavity optomechanical sensing system
NASA Astrophysics Data System (ADS)
Miao, Houxun; Srinivasan, Kartik; Aksyuk, Vladimir
2012-07-01
Microelectromechanical systems (MEMS) have been applied to many measurement problems in physics, chemistry, biology and medicine. In parallel, cavity optomechanical systems have achieved quantum-limited displacement sensitivity and ground state cooling of nanoscale objects. By integrating a novel cavity optomechanical structure into an actuated MEMS sensing platform, we demonstrate a system with high-quality-factor interferometric readout, electrical tuning of the optomechanical coupling by two orders of magnitude and a mechanical transfer function adjustable via feedback. The platform separates optical and mechanical components, allowing flexible customization for specific scientific and commercial applications. We achieve a displacement sensitivity of 4.6 fm Hz-1/2 and a force sensitivity of 53 aN Hz-1/2 with only 250 nW optical power launched into the sensor. Cold-damping feedback is used to reduce the thermal mechanical vibration of the sensor by three orders of magnitude and to broaden the sensor bandwidth by approximately the same factor, to above twice the fundamental frequency of ≈40 kHz. The readout sensitivity approaching the standard quantum limit is combined with MEMS actuation in a fully integrated, compact, low-power, stable system compatible with Si batch fabrication and electronics integration.
Nonlinear coupling between a nitrogen-vacancy-center ensemble and a superconducting qubit.
Chen, Qiong; Wen, Jun; Yang, W L; Feng, M; Du, Jiangfeng
2015-01-26
By exchange of virtual microwave photon induced by a transmission line resonator, the nonlinear interaction between a nitrogen-vacancy-center ensemble (NVE) and a superconducting charge qubit is achieved in circuit quantum electrodynamics, where the nonlinear coupling results from the second order of the coupling between the magnetic field of the transmission line resonator and the charge qubit. In our case, the nonlinear coupling can be much enhanced by a factor of the total spin number in the NVE. As an application, we present a potentially practical scheme to realize the squeezing of the NVE using the nonlinear coupling, which is within reach of the currently available technology. PMID:25835919
Integrability and chaos in nonlinearly coupled optical beams
David, D.
1989-01-01
This paper presents a study, using dynamical systems methods, of the equations describing the polarization behavior of two nonlinearly coupled optical beams counterpropagating in a nonlinear medium. In the travelling-wave regime assumption, this system possesses a Lie-Poisson structure on the manifold C{sup 2} {times} C{sup 2}. In the case where the medium is assumed to be isotropic, this system exhibits invariance under the Hamiltonian action of two copies of the rotation group, S{sup 1}, and actually reduces to a lower-dimensional system on the two-sphere, S{sup 2}. We study the dynamics on the reduced space and examine the structure of the phase portrait by determining the fixed points and infinite-period homoclinic and heteroclinic orbits; we concentrate on presenting some exotic behaviour that occurs when some parameters are varied, and we also show special solutions associated with some of the above-mentioned orbits. Last, we demonstrate the existence of complex dynamics when the system is subject to certain classes of Hamiltonian perturbations. To this end, we make use of the Melnikov method to analytically show the occurrence of either horseshoe chaos, or Arnold diffusion. 19 refs.
NASA Astrophysics Data System (ADS)
Ming, Yi; Li, Hui-Min; Ding, Ze-Jun
2016-03-01
Thermal rectification and negative differential thermal conductance were realized in harmonic chains in this work. We used the generalized Caldeira-Leggett model to study the heat flow. In contrast to most previous studies considering only the linear system-bath coupling, we considered the nonlinear system-bath coupling based on recent experiment [Eichler et al., Nat. Nanotech. 6, 339 (2011), 10.1038/nnano.2011.71]. When the linear coupling constant is weak, the multiphonon processes induced by the nonlinear coupling allow more phonons transport across the system-bath interface and hence the heat current is enhanced. Consequently, thermal rectification and negative differential thermal conductance are achieved when the nonlinear couplings are asymmetric. However, when the linear coupling constant is strong, the umklapp processes dominate the multiphonon processes. Nonlinear coupling suppresses the heat current. Thermal rectification is also achieved. But the direction of rectification is reversed compared to the results of weak linear coupling constant.
Preservation Macroscopic Entanglement of Optomechanical Systems in non-Markovian Environment
Cheng, Jiong; Zhang, Wen-Zhao; Zhou, Ling; Zhang, Weiping
2016-01-01
We investigate dynamics of an optomechanical system under the non-Markovian environment. In the weak optomechanical single-photon coupling regime, we provide an analytical approach fully taking into account the non-Markovian memory effects. When the cavity-bath coupling strength crosses a certain threshold, an oscillating memory state for the classical cavity field is formed. Due to the existence of the non-decay optical bound state, a nonequilibrium optomechanical thermal entanglement is preserved even without external driving laser. Our results provide a potential usage to generate and protect entanglement via non-Markovian environment. PMID:27032674
Preservation Macroscopic Entanglement of Optomechanical Systems in non-Markovian Environment.
Cheng, Jiong; Zhang, Wen-Zhao; Zhou, Ling; Zhang, Weiping
2016-01-01
We investigate dynamics of an optomechanical system under the non-Markovian environment. In the weak optomechanical single-photon coupling regime, we provide an analytical approach fully taking into account the non-Markovian memory effects. When the cavity-bath coupling strength crosses a certain threshold, an oscillating memory state for the classical cavity field is formed. Due to the existence of the non-decay optical bound state, a nonequilibrium optomechanical thermal entanglement is preserved even without external driving laser. Our results provide a potential usage to generate and protect entanglement via non-Markovian environment. PMID:27032674
Preservation Macroscopic Entanglement of Optomechanical Systems in non-Markovian Environment
NASA Astrophysics Data System (ADS)
Cheng, Jiong; Zhang, Wen-Zhao; Zhou, Ling; Zhang, Weiping
2016-04-01
We investigate dynamics of an optomechanical system under the non-Markovian environment. In the weak optomechanical single-photon coupling regime, we provide an analytical approach fully taking into account the non-Markovian memory effects. When the cavity-bath coupling strength crosses a certain threshold, an oscillating memory state for the classical cavity field is formed. Due to the existence of the non-decay optical bound state, a nonequilibrium optomechanical thermal entanglement is preserved even without external driving laser. Our results provide a potential usage to generate and protect entanglement via non-Markovian environment.
NASA Astrophysics Data System (ADS)
Mattei, P.-O.; Ponçot, R.; Pachebat, M.; Côte, R.
2016-07-01
In order to control the sound radiation by a structure, one aims to control vibration of radiating modes of vibration using "Energy Pumping" also named "Targeted Energy Transfer". This principle is here applied to a simplified model of a double leaf panel. This model is made of two beams coupled by a spring. One of the beams is connected to a nonlinear absorber. This nonlinear absorber is made of a 3D-printed support on which is clamped a buckled thin small beam with a small mass fixed at its centre having two equilibrium positions. The experiments showed that, once attached onto a vibrating system to be controlled, under forced excitation of the primary system, the light bistable oscillator allows a reduction of structural vibration up to 10 dB for significant amplitude and frequency range around the first two vibration modes of the system.
Optomechanical Quantum Control of a Nitrogen-Vacancy Center in Diamond
NASA Astrophysics Data System (ADS)
Golter, D. Andrew; Oo, Thein; Amezcua, Mayra; Stewart, Kevin A.; Wang, Hailin
2016-04-01
We demonstrate optomechanical quantum control of the internal electronic states of a diamond nitrogen-vacancy (NV) center in the resolved-sideband regime by coupling the NV to both optical fields and surface acoustic waves via a phonon-assisted optical transition and by taking advantage of the strong excited-state electron-phonon coupling of a NV center. Optomechanically driven Rabi oscillations as well as quantum interferences between the optomechanical sideband and the direct dipole-optical transitions are realized. These studies open the door to using resolved-sideband optomechanical coupling for quantum control of both the atomlike internal states and the motional states of a coupled NV-nanomechanical system, leading to the development of a solid-state analog of trapped ions.
Optomechanical Quantum Control of a Nitrogen-Vacancy Center in Diamond.
Golter, D Andrew; Oo, Thein; Amezcua, Mayra; Stewart, Kevin A; Wang, Hailin
2016-04-01
We demonstrate optomechanical quantum control of the internal electronic states of a diamond nitrogen-vacancy (NV) center in the resolved-sideband regime by coupling the NV to both optical fields and surface acoustic waves via a phonon-assisted optical transition and by taking advantage of the strong excited-state electron-phonon coupling of a NV center. Optomechanically driven Rabi oscillations as well as quantum interferences between the optomechanical sideband and the direct dipole-optical transitions are realized. These studies open the door to using resolved-sideband optomechanical coupling for quantum control of both the atomlike internal states and the motional states of a coupled NV-nanomechanical system, leading to the development of a solid-state analog of trapped ions. PMID:27104709
Light-induced optomechanical forces in graphene waveguides
NASA Astrophysics Data System (ADS)
Guizal, Brahim; Antezza, Mauro
2016-03-01
We show that the electromagnetic forces generated by the excitations of a mode in graphene-based optomechanical systems are highly tunable by varying the graphene chemical potential, and orders of magnitude stronger than usual non-graphene-based devices, in both attractive and repulsive regimes. We analyze coupled waveguides made of two parallel graphene sheets, either suspended or supported by dielectric slabs, and study the interplay between the light-induced force and the Casimir-Lifshitz interaction. These findings pave the way to advanced possibilities of control and fast modulation for optomechanical devices and sensors at the nano- and microscales.
Sensing dispersive and dissipative forces by an optomechanical cavity
NASA Astrophysics Data System (ADS)
Suchoi, Oren; Buks, Eyal
2016-07-01
We experimentally study an optomechanical cavity that is formed between a mechanical resonator, which serves as a movable mirror, and a stationary on-fiber dielectric mirror. A significant change in the behavior of the system is observed when the distance between the fiber's tip and the mechanical resonator is made smaller than about 1 μ \\text{m} . The combined influence of Casimir force, Coulomb interaction due to trapped charges, and optomechanical coupling is theoretically analyzed. The comparison between experimental results and theory yields a partial agreement.
Steady-state entanglement activation in optomechanical cavities
NASA Astrophysics Data System (ADS)
Farace, Alessandro; Ciccarello, Francesco; Fazio, Rosario; Giovannetti, Vittorio
2014-02-01
Quantum discord, and related indicators, are raising a relentless interest as a novel paradigm of nonclassical correlations beyond entanglement. Here, we discover a discord-activated mechanism yielding steady-state entanglement production in a realistic continuous-variable setup. This comprises two coupled optomechanical cavities, where the optical modes (OMs) communicate through a fiber. We first use a simplified model to highlight the creation of steady-state discord between the OMs. We show next that such discord improves the level of stationary optomechanical entanglement attainable in the system, making it more robust against temperature and thermal noise.
Opto-mechanics with sub-wavelength grating-membranes
NASA Astrophysics Data System (ADS)
Xu, Haitan; Kemiktarak, Utku; Stambaugh, Corey; Durand, Mathieu; Lawall, John; Taylor, Jacob
2014-03-01
We fabricate highly reflective sub-wavelength grating membranes using stoichiometric silicon nitride. We achieve a grating reflectivity of 99.6% with a membrane mechanical frequency of ~1 MHz. We integrate the grating-membrane into a Fabry-Perot cavity and investigate its opto-mechanical properties. We also consider the prospect of using them for three mode opto-mechanics experiments where the two optical cavity modes are coupled through a mechanical mode. We acknowledge support from DARPA QuASAR and the NSF-funded Physics Frontier Center at the Joint Quantum Institute, and also CNST at NIST.
Cavity optomechanics with ultrahigh-Q crystalline microresonators
Hofer, J.; Schliesser, A.; Kippenberg, T. J.
2010-09-15
We present the observation of optomechanical coupling in crystalline whispering-gallery-mode (WGM) resonators. The high purity of the material enables optical quality factors in excess of 10{sup 10} and finesse exceeding 10{sup 6}, as well as mechanical quality factors greater than 10{sup 5}. Ultrasensitive displacement measurements reveal mechanical radial modes at frequencies up to 20 MHz, corresponding to unprecedentedly high sideband factors (>100). In combination with the weak intrinsic mechanical damping this renders crystalline WGM microresonators promising for experiments in the classical and quantum regime of optomechanics.
Using interference for high fidelity quantum state transfer in optomechanics
NASA Astrophysics Data System (ADS)
Wang, Ying-Dan; Clerk, Aashish A.
2012-02-01
We present a theoretical study of a two-cavity optomechanical system (e.g. a single mechanical resonator coupled to both a microwave and an optical cavity), investigating how interference can be used to perform mechanically-mediated quantum state transfer between the two cavities. We show that this optomechanical system possesses an effective ``mechanically-dark'' mode which is immune to mechanical dissipation; utilizing this feature allows highly efficient transfer of intra-cavity states, as well as of itinerant photon states. Simple analytic expressions for the fidelity of transferring both Gaussian and non-Gaussian states are provided. Our work has relevance to ongoing experimental efforts in quantum optomechanics (e.g., C. A. Regal and K. W. Lehnert, J. Phys.: Conf. Ser. 264, 012025 (2011); A. H. Safavi-Naeini and O. Painter, New J. Phys. 13, 013017 (2011)).
Atom mediated sensing in a hybrid optomechanical system
NASA Astrophysics Data System (ADS)
Steinke, Steven; Bariani, Francesco; Singh, Swati; Meystre, Pierre; Vengalattore, Mukund
2014-05-01
A primary difficulty in implementing quantum optomechanical protocols is the requirement to operate in the good cavity limit, i.e., where the cavity linewidth is far smaller than the mechanical frequency. We explore a hybrid two cavity approach in which a membrane-in-the-middle optomechanical cavity is coupled to a second, atomic cavity. Specifically, we show that it is possible to detect the motion of the membrane via an indirect measurement of the atoms. In the case of a non-ideal optomechanical cavity, we show that the sensitivity can be enhanced via this indirect detection. Finally, we investigate the quantum limitations of such a measurement scheme. Supported by the DARPA QuASAR program through a grant from AFOSR and the DARPA ORCHID program through a grant from ARO, the US Army Research Office, and by NSF. M. V. acknowledges support from the Alfred P. Sloan Foundation.
Optomechanics for absolute rotation detection
NASA Astrophysics Data System (ADS)
Davuluri, Sankar
2016-07-01
In this article, we present an application of optomechanical cavity for the absolute rotation detection. The optomechanical cavity is arranged in a Michelson interferometer in such a way that the classical centrifugal force due to rotation changes the length of the optomechanical cavity. The change in the cavity length induces a shift in the frequency of the cavity mode. The phase shift corresponding to the frequency shift in the cavity mode is measured at the interferometer output to estimate the angular velocity of absolute rotation. We derived an analytic expression to estimate the minimum detectable rotation rate in our scheme for a given optomechanical cavity. Temperature dependence of the rotation detection sensitivity is studied.
Hybrid optomechanics for Quantum Technologies
NASA Astrophysics Data System (ADS)
Rogers, B.; Lo Gullo, N.; De Chiara, G.; Palma, G. M.; Paternostro, M.
2014-06-01
We review the physics of hybrid optomechanical systems consisting of a mechanical oscillator interacting with both a radiation mode and an additional matterlike system. We concentrate on the cases embodied by either a single or a multi-atom system (a Bose-Einstein condensate, in particular) and discuss a wide range of physical effects, from passive mechanical cooling to the set-up of multipartite entanglement, from optomechanical nonlocality to the achievement of non-classical states of a single mechanical mode. The reviewed material showcases the viability of hybridised cavity optomechanical systems as basic building blocks for quantum communication networks and quantum state-engineering devices, possibly empowered by the use of quantum and optimal control techniques. The results that we discuss are instrumental to the promotion of hybrid optomechanical devices as promising experimental platforms for the study of nonclassicality at the genuine mesoscopic level.
Optical Nonreciprocity in Optomechanical Structures
NASA Astrophysics Data System (ADS)
Manipatruni, Sasikanth; Robinson, Jacob T.; Lipson, Michal
2009-05-01
We demonstrate that optomechanical devices can exhibit nonreciprocal behavior when the dominant light-matter interaction takes place via a linear momentum exchange between light and the mechanical structure. As an example, we propose a microscale optomechanical device that can exhibit a nonreciprocal behavior in a microphotonic platform operating at room temperature. We show that, depending on the direction of the incident light, the device switches between a high and low transparency state with more than a 20 dB extinction ratio.
Optical-response properties in levitated optomechanical systems beyond the low-excitation limit
NASA Astrophysics Data System (ADS)
Nie, Wenjie; Chen, Aixi; Lan, Yueheng
2016-02-01
We investigate the optical-response properties of a levitated optomechanical cavity coupled to a higher order excited atomic medium. The cavity field driven through the atom-field interaction is responsible for trapping a dielectric nanosphere, whose steady-state position is biased by the Coulomb force between the nanosphere and the cavity wall. We show that the phenomena of optomechanically induced transparency (OMIT) and amplification can be generated from the output probe field in the presence of an effective optomechanical coupling between the nanosphere and the cavity field. Further, the width of the transparency window increases with increasing strength of the effective optomechanical coupling, which is controlled easily by varying the Coulomb interaction and the radius of the nanosphere. In particular, when the higher order excitation of the atomic medium is included, a large driving of the atomic ensemble but a relatively small atom-field detuning can be applied to help observe the OMIT behavior in the hybrid system.
Parametric Optomechanical Oscillations in Two-dimensional Slot-type High-Q Photonic Crystal Cavities
Zheng J.; Stein A.; Li, Y.; Aras, M.S.; Shepard, K.L.; Wong, C.W.
2012-05-22
We experimentally demonstrate an optomechanical cavity based on an air-slot photonic crystal cavity with optical quality factor Q{sub o} = 4.2 x 10{sup 4} and a small modal volume of 0.05 cubic wavelengths. The optical mode is coupled with the in-plane mechanical modes with frequencies up to hundreds of MHz. The fundamental mechanical mode shows a frequency of 65 MHz and a mechanical quality factor of 376. The optical spring effect, optical damping, and amplification are observed with a large experimental optomechanical coupling rate g{sub om}/2{pi} of 154 GHz/nm, corresponding to a vacuum optomechanical coupling rate g*/2{pi} of 707 kHz. With sub-mW or less input power levels, the cavity exhibits strong parametric oscillations. The phase noise of the photonic crystal optomechanical oscillator is also measured.
Tunable bistability in hybrid Bose-Einstein condensate optomechanics.
Yasir, Kashif Ammar; Liu, Wu-Ming
2015-01-01
Cavity-optomechanics, a rapidly developing area of research, has made a remarkable progress. A stunning manifestation of optomechanical phenomena is in exploiting the mechanical effects of light to couple the optical degree of freedom with mechanical degree of freedom. In this report, we investigate the controlled bistable dynamics of such hybrid optomechanical system composed of cigar-shaped Bose-Einstein condensate (BEC) trapped inside high-finesse optical cavity with one moving-end mirror and is driven by a single mode optical field. The numerical results provide evidence for controlled optical bistability in optomechanics using transverse optical field which directly interacts with atoms causing the coupling of transverse field with momentum side modes, exited by intra-cavity field. This technique of transverse field coupling is also used to control bistable dynamics of both moving-end mirror and BEC. The report provides an understanding of temporal dynamics of moving-end mirror and BEC with respect to transverse field. Moreover, dependence of effective potential of the system on transverse field has also been discussed. To observe this phenomena in laboratory, we have suggested a certain set of experimental parameters. These findings provide a platform to investigate the tunable behavior of novel phenomenon like electromagnetically induced transparency and entanglement in hybrid systems. PMID:26035206
NASA Astrophysics Data System (ADS)
Lamarque, C.-H.; Ture Savadkoohi, A.; Naudan, M.
2013-09-01
The concept of energy exchange between coupled oscillators can be endowed for wide variety of applications such as control and energy harvesting. It has been proved that by coupling an essential nonlinear oscillator (cubic nonlinearity) to a main system (mostly linear), the latter system can be controlled in a one way and almost irreversible manner. The phenomenon is called energy pumping and the coupled nonlinear system is named as nonlinear energy sink (NES). The process of energy transfer from the main system to the nonlinear smooth or non-smooth attachment at different scales of time can present several scenarios: It can be attracted to periodic behaviors which present low or high energy levels for the main system and/or to quasi-periodic responses of two oscillators by persistent bifurcations between their stable zones. In this paper we analyze multi-scale dynamics of two attached oscillators: a Bouc-Wen type in general (in particular: a Dahl type and a modified hysteresis system) and a NES (nonsmooth and cubic). The system behavior at fast and first slow times scales by detecting its invariant manifold, its fixed points and singularities will be analyzed. Analytical developments will be accompanied by some numerical examples for systems that present quasi-periodic responses. The endowed Bouc-Wen models correspond to the hysteretic behavior of materials or structures. This paper is clearly connected with the dynamics of systems with hysteresis and nonlinear dynamics based energy harvesting.
Tunable two-photon correlation in a double-cavity optomechanical system
Feng, Zhi-Bo; Zhang, Jian-Qi
2015-12-15
Correlated photons are essential sources for quantum information processing. We propose a practical scheme to generate pairs of correlated photons in a controllable fashion from a double-cavity optomechanical system, where the variable optomechanical coupling strength makes it possible to tune the photon correlation at our will. The key operation is based on the repulsive or attractive interaction between the two photons intermediated by the mechanical resonator. The present protocol could provide a potential approach to coherent control of the photon correlation using the optomechanical cavity.
Coupling of two counterpropagating modes in nonlinear split-ring resonators' chain
NASA Astrophysics Data System (ADS)
Cui, Wei-na; Lu, Wen; Li, Hong-xia; Sun, Min; Zhu, Yong-yuan
2016-05-01
The two coupled counterpropagating nonlinear magnetoinductive wave modes are analyzed theoretically in split ring resonator chain with Kerr nonlinear interaction. Starting from a general nonlinear lattice equation based on a quasi-discreteness approach we derive two coupled nonlinear Schrödinger equations governing the evolution of the slowly varying envelopes of these modes. It is shown that this system supports backward- and forward-propagating vector solitons of the bright-bright and dark-dark type through a cross-phase modulation.
Multifunctional optomechanical dynamics in integrated silicon photonics
NASA Astrophysics Data System (ADS)
Li, Huan
Light can generate forces on matter. The nature of these forces is electromagnetic force, or Lorentz force. The emergence and rapid progress of nanotechnology provided an unprecedented platform where the very feeble optical forces began to play significant roles. The interactions between light and matter in nanoscale has been the focus of almost a decade of active theoretical and experimental investigations, which are still ongoing and constitute a whole new burgeoning branch of nanotechnology, nano-optomechanical systems (NOMS). In such context, the general goal of my research is to generate, enhance and control optical forces on silicon photonics platforms, with a focus on developing new functionalities and demonstrating novel effects, which will potentially lead to a new class of silicon photonic devices for a broad spectrum of applications. In this dissertation, the concept of optical force and the general background of the NOMS research area are first introduced. The general goal of the silicon photonics research area and the research presented in this dissertation is then described. Subsequently, the fundamental theory for optical force is summarized. The different methods to calculate optical forces are enumerated and briefly reviewed. Integrated hybrid plasmonic waveguide (HPWG) devices have been successfully fabricated and the enhanced optical forces experimentally measured for the first time. All-optical amplification of RF signals has been successfully demonstrated. The optical force generated by one laser is used to mechanically change the optical path and hence the output power of another laser. In addition, completely optically tunable mechanical nonlinear behavior has been demonstrated for the first time and systematically studied. Optomechanical photon shuttling between photonic cavities has been demonstrated with a "photon see-saw" device. This photon see-saw is a novel multicavity optomechanical device which consists of two photonic crystal
Coupled Particle Transport and Pattern Formation in a Nonlinear Leaky-Box Model
NASA Technical Reports Server (NTRS)
Barghouty, A. F.; El-Nemr, K. W.; Baird, J. K.
2009-01-01
Effects of particle-particle coupling on particle characteristics in nonlinear leaky-box type descriptions of the acceleration and transport of energetic particles in space plasmas are examined in the framework of a simple two-particle model based on the Fokker-Planck equation in momentum space. In this model, the two particles are assumed coupled via a common nonlinear source term. In analogy with a prototypical mathematical system of diffusion-driven instability, this work demonstrates that steady-state patterns with strong dependence on the magnetic turbulence but a rather weak one on the coupled particles attributes can emerge in solutions of a nonlinearly coupled leaky-box model. The insight gained from this simple model may be of wider use and significance to nonlinearly coupled leaky-box type descriptions in general.
Nonlinear dynamics of magnetically coupled beams for multi-modal vibration energy harvesting
NASA Astrophysics Data System (ADS)
Abed, I.; Kacem, N.; Bouhaddi, N.; Bouazizi, M. L.
2016-04-01
We investigate the nonlinear dynamics of magnetically coupled beams for multi-modal vibration energy harvesting. A multi-physics model for the proposed device is developed taking into account geometric and magnetic nonlinearities. The coupled nonlinear equations of motion are solved using the Galerkin discretization coupled with the harmonic balance method and the asymptotic numerical method. Several numerical simulations have been performed showing that the expected performances of the proposed vibration energy harvester are significantly promising with up to 130 % in term of bandwidth and up to 60 μWcm-3g-2 in term of normalized harvested power.
Degenerate optomechanical parametric oscillators: Cooling in the vicinity of a critical point
NASA Astrophysics Data System (ADS)
Degenfeld-Schonburg, Peter; Abdi, Mehdi; Hartmann, Michael J.; Navarrete-Benlloch, Carlos
2016-02-01
Degenerate optomechanical parametric oscillators are optical resonators in which a mechanical degree of freedom is coupled to a cavity mode that is nonlinearly amplified via parametric down-conversion of an external pumping laser. Below a critical pumping power the down-converted field is purely quantum mechanical, making the theoretical description of such systems very challenging. Here we introduce a theoretical approach that is capable of describing this regime, even at the critical point itself. We find that the down-converted field can induce significant mechanical cooling and identify the process responsible of this as a cooling-by-heating mechanism. Moreover, we show that, contrary to naive expectations and semiclassical predictions, cooling is not optimal at the critical point, where the photon number is largest. Our approach opens the possibility of analyzing further hybrid dissipative quantum systems in the vicinity of critical points.
Xiong, Hao; Si, Liu-Gang; Lü, Xin-You; Yang, Xiaoxue; Wu, Ying
2014-10-15
We propose an interesting scheme for tunable high-order sideband comb generation by utilizing ultrastrong optomechanical interaction in a GaAs optomechanical disk resonator beyond the perturbative approximation. We analyze the nonlinear nature of the optomechanical interaction, and give a full description of the non-perturbative effects. It is shown, within the non-perturbative regime, that high-order sideband comb with large intensities can be realized and controlled in a GaAs optomechanical disk resonator with experimentally achievable system parameters, and the non-perturbative regime leads to rich and nontrivial behavior.
Cavity-less on-chip optomechanics using excitonic transitions in semiconductor heterostructures
NASA Astrophysics Data System (ADS)
Okamoto, Hajime; Watanabe, Takayuki; Ohta, Ryuichi; Onomitsu, Koji; Gotoh, Hideki; Sogawa, Tetsuomi; Yamaguchi, Hiroshi
2015-10-01
The hybridization of semiconductor optoelectronic devices and nanomechanical resonators provides a new class of optomechanical systems in which mechanical motion can be coupled to light without any optical cavities. Such cavity-less optomechanical systems interconnect photons, phonons and electrons (holes) in a highly integrable platform, opening up the development of functional integrated nanomechanical devices. Here we report on a semiconductor modulation-doped heterostructure-cantilever hybrid system, which realizes efficient cavity-less optomechanical transduction through excitons. The opto-piezoelectric backaction from the bound electron-hole pairs enables us to probe excitonic transition simply with a sub-nanowatt power of light, realizing high-sensitivity optomechanical spectroscopy. Detuning the photon energy from the exciton resonance results in self-feedback cooling and amplification of the thermomechanical motion. This cavity-less on-chip coupling enables highly tunable and addressable control of nanomechanical resonators, allowing high-speed programmable manipulation of nanomechanical devices and sensor arrays.
Cavity-less on-chip optomechanics using excitonic transitions in semiconductor heterostructures.
Okamoto, Hajime; Watanabe, Takayuki; Ohta, Ryuichi; Onomitsu, Koji; Gotoh, Hideki; Sogawa, Tetsuomi; Yamaguchi, Hiroshi
2015-01-01
The hybridization of semiconductor optoelectronic devices and nanomechanical resonators provides a new class of optomechanical systems in which mechanical motion can be coupled to light without any optical cavities. Such cavity-less optomechanical systems interconnect photons, phonons and electrons (holes) in a highly integrable platform, opening up the development of functional integrated nanomechanical devices. Here we report on a semiconductor modulation-doped heterostructure-cantilever hybrid system, which realizes efficient cavity-less optomechanical transduction through excitons. The opto-piezoelectric backaction from the bound electron-hole pairs enables us to probe excitonic transition simply with a sub-nanowatt power of light, realizing high-sensitivity optomechanical spectroscopy. Detuning the photon energy from the exciton resonance results in self-feedback cooling and amplification of the thermomechanical motion. This cavity-less on-chip coupling enables highly tunable and addressable control of nanomechanical resonators, allowing high-speed programmable manipulation of nanomechanical devices and sensor arrays. PMID:26477487
NASA Astrophysics Data System (ADS)
Vainsencher, Amit; Satzinger, K. J.; Peairs, G. A.; Cleland, A. N.
2016-07-01
We describe the principles of design, fabrication, and operation of a piezoelectric optomechanical crystal with which we demonstrate bi-directional conversion of energy between microwave and optical frequencies. The optomechanical crystal has an optical mode at 1523 nm co-located with a mechanical breathing mode at 3.8 GHz, with a measured optomechanical coupling strength gom/2π of 115 kHz. The breathing mode is driven and detected by curved interdigitated transducers that couple to a Lamb mode in suspended membranes on either end of the optomechanical crystal, allowing the external piezoelectric modulation of the optical signal as well as the converse, the detection of microwave electrical signals generated by a modulated optical signal. We compare measurements to theory where appropriate.
Cavity-less on-chip optomechanics using excitonic transitions in semiconductor heterostructures
Okamoto, Hajime; Watanabe, Takayuki; Ohta, Ryuichi; Onomitsu, Koji; Gotoh, Hideki; Sogawa, Tetsuomi; Yamaguchi, Hiroshi
2015-01-01
The hybridization of semiconductor optoelectronic devices and nanomechanical resonators provides a new class of optomechanical systems in which mechanical motion can be coupled to light without any optical cavities. Such cavity-less optomechanical systems interconnect photons, phonons and electrons (holes) in a highly integrable platform, opening up the development of functional integrated nanomechanical devices. Here we report on a semiconductor modulation-doped heterostructure–cantilever hybrid system, which realizes efficient cavity-less optomechanical transduction through excitons. The opto-piezoelectric backaction from the bound electron–hole pairs enables us to probe excitonic transition simply with a sub-nanowatt power of light, realizing high-sensitivity optomechanical spectroscopy. Detuning the photon energy from the exciton resonance results in self-feedback cooling and amplification of the thermomechanical motion. This cavity-less on-chip coupling enables highly tunable and addressable control of nanomechanical resonators, allowing high-speed programmable manipulation of nanomechanical devices and sensor arrays. PMID:26477487
Tunable Optomechanically Induced Absorption in a Hybrid Optomechanical System
NASA Astrophysics Data System (ADS)
Wang, Qiong; Zhao, Yun-Hui; He, Zhi; Yao, Chun-Mei
2016-03-01
We study the tunable optomechanically induced absorption (OMIA) with the quantized field in the system, which consists of a driven cavity and a mechanical resonator with a super-conducting charge qubit via Jaynes-Cummings interaction. Such a OMIA can be achieved by controlling the strength of the Jaynes-Cummings interaction. Moreover, our work shows this OMIA for the quantized fields can be robust against cavity decay in somehow. With the combination of optomechanically induced transparency (OMIT), our proposal may have paved a new avenue towards quantum photon router.
Optomechanics of two- and three-dimensional soft photonic crystals
NASA Astrophysics Data System (ADS)
Krishnan, Dwarak
Soft photonic crystals are a class of periodic dielectric structures that undergo highly nonlinear deformation due to strain or other external stimulus such as temperature, pH etc. This can in turn dramatically affect optical properties such as light transmittance. Moreover certain classes of lithographically fabricated structures undergo some structural distortion due to the effects of processing, eventually affecting the optical properties of the final photonic crystal. In this work, we study the deformation mechanics of soft photonic crystal structures using realistic physics-based models and leverage that understanding to explain the optomechanics of actual 2-D and 3-D soft photonic crystals undergoing similar symmetry breaking nonlinear deformations. We first study the optomechanics of two classes of 3-D soft photonic crystals: (1) hydrogel and (2) elastomer based material systems. The hydrogel based inverse face-centered-cubic structure undergoes swelling with change in pH of the surrounding fluid. The inverse structure is a network of bulky domains with thin ligament-like connections, and it undergoes a pattern transformation from FCC to L11 as a result of swelling. A continuum scale poroelasticity based coupled fluid-diffusion FEM model is developed to accurately predict this mechanical behavior. Light transmittance simulation results qualitatively explain the experimentally observed trends in the optical behavior with pH change. The elastomer based, lithographically fabricated material experiences shrinkage induced distortion upon processing. This behavior is modeled using FEM with the material represented by a neo-Hookean constitutive law. The light transmittance calculations for normal incidence are carried out using the transfer matrix method and a good comparison is obtained for the positions of first and second order reflectance peaks. A unit cell based approach is taken to compute the photonic bandstructure to estimate light propagation through the
On the importance of nonlinear couplings in large-scale neutrino streams
NASA Astrophysics Data System (ADS)
Dupuy, Hélène; Bernardeau, Francis
2015-08-01
We propose a procedure to evaluate the impact of nonlinear couplings on the evolution of massive neutrino streams in the context of large-scale structure growth. Such streams can be described by general nonlinear conservation equations, derived from a multiple-flow perspective, which generalize the conservation equations of non-relativistic pressureless fluids. The relevance of the nonlinear couplings is quantified with the help of the eikonal approximation applied to the subhorizon limit of this system. It highlights the role played by the relative displacements of different cosmic streams and it specifies, for each flow, the spatial scales at which the growth of structure is affected by nonlinear couplings. We found that, at redshift zero, such couplings can be significant for wavenumbers as small as k=0.2 h/Mpc for most of the neutrino streams.
A micropillar for cavity optomechanics
NASA Astrophysics Data System (ADS)
Kuhn, Aurélien; Neuhaus, Leonhard; Van Brackel, Emmanuel; Chartier, Claude; Ducloux, Olivier; Le Traon, Olivier; Michel, Christophe; Pinard, Laurent; Flaminio, Raffaele; Deléglise, Samuel; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine
2014-12-01
Demonstrating the quantum ground state of a macroscopic mechanical object is a major experimental challenge in physics, at the origin of the rapid emergence of cavity optomechanics. We have developed a new generation of optomechanical devices, based on a microgram quartz micropillar with a very high mechanical quality factor. The structure is used as end mirror in a Fabry-Perot cavity with a high optical finesse, leading to ultra-sensitive interferometric measurement of the resonator displacement. We expect to reach the ground state of this optomechanical resonator by combining cryogenic cooling in a dilution fridge at 30 mK and radiation-pressure cooling. We have already carried out a quantum-limited measurement of the micropillar thermal noise at low temperature.
A micropillar for cavity optomechanics
Kuhn, Aurélien; Neuhaus, Leonhard; Deléglise, Samuel; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine; Van Brackel, Emmanuel; Chartier, Claude; Ducloux, Olivier; Le Traon, Olivier; Michel, Christophe; Pinard, Laurent; Flaminio, Raffaele
2014-12-04
Demonstrating the quantum ground state of a macroscopic mechanical object is a major experimental challenge in physics, at the origin of the rapid emergence of cavity optomechanics. We have developed a new generation of optomechanical devices, based on a microgram quartz micropillar with a very high mechanical quality factor. The structure is used as end mirror in a Fabry-Perot cavity with a high optical finesse, leading to ultra-sensitive interferometric measurement of the resonator displacement. We expect to reach the ground state of this optomechanical resonator by combining cryogenic cooling in a dilution fridge at 30 mK and radiation-pressure cooling. We have already carried out a quantum-limited measurement of the micropillar thermal noise at low temperature.
On the HAM-based mathematica package BVPh for coupled nonlinear ODEs
NASA Astrophysics Data System (ADS)
Zhao, Yinlong; Liao, Shijun
2012-09-01
The BVPh is a Mathematica package based on the Homotopy analysis method (HAM) for solving nonlinear boundary value problems (BVPs). Its aim is to provide an analytic tool for as many nonlinear BVPs as possible. Its newest version can now deal with many systems of coupled ordinary differential equations (ODEs) defined in finite or semi-infinite intervals.
Nonlinear coupling of left and right handed circularly polarized dispersive Alfvén wave
Sharma, R. P. Sharma, Swati Gaur, Nidhi
2014-07-15
The nonlinear phenomena are of prominent interests in understanding the particle acceleration and transportation in the interplanetary space. The ponderomotive nonlinearity causing the filamentation of the parallel propagating circularly polarized dispersive Alfvén wave having a finite frequency may be one of the mechanisms that contribute to the heating of the plasmas. The contribution will be different of the left (L) handed mode, the right (R) handed mode, and the mix mode. The contribution also depends upon the finite frequency of the circularly polarized waves. In the present paper, we have investigated the effect of the nonlinear coupling of the L and R circularly polarized dispersive Alfvén wave on the localized structures formation and the respective power spectra. The dynamical equations are derived in the presence of the ponderomotive nonlinearity of the L and R pumps and then studied semi-analytically as well as numerically. The ponderomotive nonlinearity accounts for the nonlinear coupling between both the modes. In the presence of the adiabatic response of the density fluctuations, the nonlinear dynamical equations satisfy the modified nonlinear Schrödinger equation. The equations thus obtained are solved in solar wind regime to study the coupling effect on localization and the power spectra. The effect of coupling is also studied on Faraday rotation and ellipticity of the wave caused due to the difference in the localization of the left and the right modes with the distance of propagation.
Deterministic synthesis of mechanical NOON states in ultrastrong optomechanics
NASA Astrophysics Data System (ADS)
Macrí, V.; Garziano, L.; Ridolfo, A.; Di Stefano, O.; Savasta, S.
2016-07-01
We propose a protocol for the deterministic preparation of entangled NOON mechanical states. The system is constituted by two identical, optically coupled optomechanical systems. The protocol consists of two steps. In the first, one of the two optical resonators is excited by a resonant external π -like Gaussian optical pulse. When the optical excitation coherently partly transfers to the second cavity, the second step starts. It consists of sending simultaneously two additional π -like Gaussian optical pulses, one at each optical resonator, with specific frequencies. In the optomechanical ultrastrong coupling regime, when the coupling strength becomes a significant fraction of the mechanical frequency, we show that NOON mechanical states with quite high Fock states can be deterministically obtained. The operating range of this protocol is carefully analyzed. Calculations have been carried out taking into account the presence of decoherence, thermal noise, and imperfect cooling.
Quantum and classical phases in optomechanics
NASA Astrophysics Data System (ADS)
Armata, Federico; Latmiral, Ludovico; Pikovski, Igor; Vanner, Michael R.; Brukner, Časlav; Kim, M. S.
2016-06-01
The control of quantum systems requires the ability to change and read-out the phase of a system. The noncommutativity of canonical conjugate operators can induce phases on quantum systems, which can be employed for implementing phase gates and for precision measurements. Here we study the phase acquired by a radiation field after its radiation pressure interaction with a mechanical oscillator, and compare the classical and quantum contributions. The classical description can reproduce the nonlinearity induced by the mechanical oscillator and the loss of correlations between mechanics and optical field at certain interaction times. Such features alone are therefore insufficient for probing the quantum nature of the interaction. Our results thus isolate genuine quantum contributions of the optomechanical interaction that could be probed in current experiments.
Electromagnetically induced transparency and slow light with optomechanics.
Safavi-Naeini, A H; Mayer Alegre, T P; Chan, J; Eichenfield, M; Winger, M; Lin, Q; Hill, J T; Chang, D E; Painter, O
2011-04-01
Controlling the interaction between localized optical and mechanical excitations has recently become possible following advances in micro- and nanofabrication techniques. So far, most experimental studies of optomechanics have focused on measurement and control of the mechanical subsystem through its interaction with optics, and have led to the experimental demonstration of dynamical back-action cooling and optical rigidity of the mechanical system. Conversely, the optical response of these systems is also modified in the presence of mechanical interactions, leading to effects such as electromagnetically induced transparency (EIT) and parametric normal-mode splitting. In atomic systems, studies of slow and stopped light (applicable to modern optical networks and future quantum networks) have thrust EIT to the forefront of experimental study during the past two decades. Here we demonstrate EIT and tunable optical delays in a nanoscale optomechanical crystal, using the optomechanical nonlinearity to control the velocity of light by way of engineered photon-phonon interactions. Our device is fabricated by simply etching holes into a thin film of silicon. At low temperature (8.7 kelvin), we report an optically tunable delay of 50 nanoseconds with near-unity optical transparency, and superluminal light with a 1.4 microsecond signal advance. These results, while indicating significant progress towards an integrated quantum optomechanical memory, are also relevant to classical signal processing applications. Measurements at room temperature in the analogous regime of electromagnetically induced absorption show the utility of these chip-scale optomechanical systems for optical buffering, amplification, and filtering of microwave-over-optical signals. PMID:21412237
Force sensitivity of multilayer graphene optomechanical devices
NASA Astrophysics Data System (ADS)
Weber, P.; Güttinger, J.; Noury, A.; Vergara-Cruz, J.; Bachtold, A.
2016-08-01
Mechanical resonators based on low-dimensional materials are promising for force and mass sensing experiments. The force sensitivity in these ultra-light resonators is often limited by the imprecision in the measurement of the vibrations, the fluctuations of the mechanical resonant frequency and the heating induced by the measurement. Here, we strongly couple multilayer graphene resonators to superconducting cavities in order to achieve a displacement sensitivity of 1.3 fm Hz-1/2. This coupling also allows us to damp the resonator to an average phonon occupation of 7.2. Our best force sensitivity, 390 zN Hz-1/2 with a bandwidth of 200 Hz, is achieved by balancing measurement imprecision, optomechanical damping, and measurement-induced heating. Our results hold promise for studying the quantum capacitance of graphene, its magnetization, and the electron and nuclear spins of molecules adsorbed on its surface.
Force sensitivity of multilayer graphene optomechanical devices
Weber, P.; Güttinger, J.; Noury, A.; Vergara-Cruz, J.; Bachtold, A.
2016-01-01
Mechanical resonators based on low-dimensional materials are promising for force and mass sensing experiments. The force sensitivity in these ultra-light resonators is often limited by the imprecision in the measurement of the vibrations, the fluctuations of the mechanical resonant frequency and the heating induced by the measurement. Here, we strongly couple multilayer graphene resonators to superconducting cavities in order to achieve a displacement sensitivity of 1.3 fm Hz−1/2. This coupling also allows us to damp the resonator to an average phonon occupation of 7.2. Our best force sensitivity, 390 zN Hz−1/2 with a bandwidth of 200 Hz, is achieved by balancing measurement imprecision, optomechanical damping, and measurement-induced heating. Our results hold promise for studying the quantum capacitance of graphene, its magnetization, and the electron and nuclear spins of molecules adsorbed on its surface. PMID:27502017
Force sensitivity of multilayer graphene optomechanical devices.
Weber, P; Güttinger, J; Noury, A; Vergara-Cruz, J; Bachtold, A
2016-01-01
Mechanical resonators based on low-dimensional materials are promising for force and mass sensing experiments. The force sensitivity in these ultra-light resonators is often limited by the imprecision in the measurement of the vibrations, the fluctuations of the mechanical resonant frequency and the heating induced by the measurement. Here, we strongly couple multilayer graphene resonators to superconducting cavities in order to achieve a displacement sensitivity of 1.3 fm Hz(-1/2). This coupling also allows us to damp the resonator to an average phonon occupation of 7.2. Our best force sensitivity, 390 zN Hz(-1/2) with a bandwidth of 200 Hz, is achieved by balancing measurement imprecision, optomechanical damping, and measurement-induced heating. Our results hold promise for studying the quantum capacitance of graphene, its magnetization, and the electron and nuclear spins of molecules adsorbed on its surface. PMID:27502017
Reservoir engineering in microwave cavity optomechanics
NASA Astrophysics Data System (ADS)
Lecocq, Florent; Clark, Jeremy; Aumentado, Jose; Simmonds, Raymond; Teufel, John
2015-03-01
Microwave cavity optomechanics is an architecture in which a freely suspended membrane modulates the frequency of a superconducting microwave resonant circuit. The resulting parametric interactions influence both the mechanical degree of freedom and the microwave light emerging from the cavity. Even at cryogenic temperatures, the mechanical oscillator resonating at 10 MHz is typically dominated by its thermal reservoir, washing out any quantum behavior. However, in the presence of coherent drives to the cavity, the bare mechanical properties can be overwhelmed by the strong opto-mechanical interactions from the light field. By choosing wisely the frequency and amplitude of the drives, one can engineer the environment seen by the mechanical oscillator, a technique known as ``reservoir engineering''. From an experimentalist point of view, I will discuss how using two-tone driving schemes, we exploit correlations in the vacuum noise to: (1) eliminate the backaction imparted on the mechanical quadrature being measured, a technique so-called Back-Action Evasion, or (2) strongly couple the mechanical mode to a squeezed microwave bath.
Vector cavity optomechanics in the parameter configuration of optomechanically induced transparency
NASA Astrophysics Data System (ADS)
Xiong, Hao; Huang, Ya-Min; Wan, Liang-Liang; Wu, Ying
2016-07-01
We propose the concept of vector cavity optomechanics in which the polarization behavior of light fields is introduced to achieve optomechanical control. The steady states and optomechanically induced transparency are studied in the vector regime, and we show that the polarization of optical fields may be a powerful tool to identify the underlying physical process and control the signal of optomechanically induced transparency. In particular, the conditions for obtaining a linearly polarized output probe field is given, which reveal some nontrivial polarizing effects. Despite its conceptual simplicity, vector cavity optomechanics may entail a wide range of intriguing phenomena and uncover a novel understanding for optomechanical interaction.
Parametrically driven field emission in strongly nonlinear coupled electron-shuttles
NASA Astrophysics Data System (ADS)
Kim, Chulki; Prada, Marta; Platero, Gloria; Seo, Minah; Lee, Taikjin; Kim, Jae Hun; Lee, Seok; Blick, Robert
2014-03-01
The transition of coupled electron shuttles from a stable to a strongly nonlinear response is demonstrated at room temperature. The electron transport is Coulomb-controlled at low voltages but changes to the conventional field emission in this transition. This reversible process forms a well-defined band within a broad frequency range in the parameter space. Both the experimental data and numerical calculations indicate that the source of the nonlinearity is provided by the electromechanical coupling. The increased current in the nonlinear regime has the potential to form the basis for energy harvesting via nanomechanical shuttles.
Delrue, Steven; Van Den Abeele, Koen
2015-12-01
Interaction of ultrasonic guided waves with kissing bonds (closed delaminations and incipient surface breaking cracks) gives rise to nonlinear features at the defect location. This causes higher harmonic frequency ultrasonic radiation into the ambient air, often referred to as Nonlinear Air-Coupled Emission (NACE), which may serve as a nonlinear tag to detect the defects. This paper summarizes the results of a numerical implementation and simulation study of NACE. The developed model combines a 3D time domain model for the nonlinear Lamb wave propagation in delaminated samples with a spectral solution for the nonlinear air-coupled emission. A parametric study is conducted to illustrate the potential of detecting defect location, size and shape by studying the NACE acoustic radiation patterns in different orientation planes. The simulation results prove that there is a good determination potential for the defect parameters, especially when the radiated frequency matches one of the resonance frequencies of the delaminated layer, leading to a Local Defect Resonance (LDR). PMID:26208725
A novel approach to synchronization of nonlinearly coupled network systems with delays
NASA Astrophysics Data System (ADS)
Tseng, Jui-Pin
2016-06-01
In this investigation, a novel approach to establishing the global synchronization of coupled network systems is presented. Under this approach, individual subsystems can be non-autonomous, and the coupling configuration is rather general. The coupling terms can be non-diffusive, nonlinear, time-dependent, asymmetric, and with time delays. With an iteration scheme, the problem of synchronization is transformed into solving a corresponding linear system of algebraic equations. Subsequently, delay-dependent and delay-independent criteria for global synchronization can be established. We implement the present approach to analyze synchronization of the FitzHugh-Nagumo systems under delayed and nonlinear sigmoidal coupling. Two examples are presented to demonstrate new dynamical scenarios, where oscillatory behavior and multistability emerge or are suppressed as the coupled neurons synchronize under the synchronization criterion. In addition, asynchrony induced by the coupling strength or coupling delay occurs while the synchronization criterion is violated.
PT-symmetric dimer of coupled nonlinear oscillators
NASA Astrophysics Data System (ADS)
Cuevas, Jesús; Kevrekidis, Panayotis G.; Saxena, Avadh; Khare, Avinash
2013-09-01
We provide a systematic analysis of a prototypical nonlinear oscillator system respecting PT symmetry i.e., one of them has gain and the other an equal and opposite amount of loss. Starting from the linear limit of the system, we extend considerations to the nonlinear case for both soft and hard cubic nonlinearities identifying symmetric and antisymmetric breather solutions, as well as symmetry-breaking variants thereof. We propose a reduction of the system to a Schrödinger-type PT-symmetric dimer, whose detailed earlier understanding can explain many of the phenomena observed herein, including the PT phase transition. Nevertheless, there are also significant parametric as well as phenomenological potential differences between the two models and we discuss where these arise and where they are most pronounced. Finally, we also provide examples of the evolution dynamics of the different states in their regimes of instability.
Fan, Cairong; Shi, Fenghua; Wu, Hongxing; Chen, Yihang
2015-06-01
Tunable all-optical plasmonic diode is proposed based on the Fano resonance in an asymmetric and nonlinear system, comprising metal-insulator-metal waveguides coupled with nanocavities. The spatial asymmetry of the system gives rise to the nonreciprocity of the field localizations at the nonlinear gap between the coupled cavities and to the nonreciprocal nonlinear response. Nonlinear Fano resonance, originating from the interference between the discrete cavity mode and the continuum traveling mode, is observed and effectively tuned by changing the input power. By combining the unidirectional nonlinear response with the steep dispersion of the Fano asymmetric line shape, a transmission contrast ratio up to 41.46 dB can be achieved between forward and backward transmission. Our all-optical plasmonic diode with compact structure can find important applications in integrated optical nanocircuits. PMID:26030529
Time domain simulation of nonlinear response of a coupled TLP system in random seas
Kim, C.H.; Kim, M.H.; Liu, Y.H.; Zhao, C.T.
1994-12-31
This paper presents a result of an analysis of the nonlinear interaction and response of the coupled ISSC-TLP System to the random seas in the time domain. The environmental load also includes the effect of the concurrent steady winds and currents. The first- and second-order wave-exciting forces are calculated using a robust higher-order boundary element method (HOBEM), while the nonlinear tendon dynamic analysis is performed using the three-dimensional hybrid element method with the upgated Lagrangian formulation. The Morison equation is employed for the wave and current load on slender structures. The analysis is focused on the nonlinear responses due to the nonlinear environmental load and nonlinear interaction between the platform and tendons that includes the offset, setdown, large coupled surge-heave motion in the low frequency and resonant heave/pitch responses with the springing loads in the high frequency.
Optimal control of the power adiabatic stroke of an optomechanical heat engine.
Bathaee, M; Bahrampour, A R
2016-08-01
We consider the power adiabatic stroke of the Otto optomechanical heat engine introduced in Phys. Rev. Lett. 112, 150602 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.150602. We derive the maximum extractable work of both optomechanical normal modes in the minimum time while the system experiences quantum friction effects. We show that the total work done by the system in the power adiabatic stroke is optimized by a bang-bang control. The time duration of the power adiabatic stroke is of the order of the inverse of the effective optomechanical-coupling coefficient. The optimal phase-space trajectory of the Otto cycle for both optomechanical normal modes is also obtained. PMID:27627280
Rogue waves for a system of coupled derivative nonlinear Schrödinger equations
NASA Astrophysics Data System (ADS)
Chan, H. N.; Malomed, B. A.; Chow, K. W.; Ding, E.
2016-01-01
Rogue waves (RWs) are unexpectedly strong excitations emerging from an otherwise tranquil background. The nonlinear Schrödinger equation (NLSE), a ubiquitous model with wide applications to fluid mechanics, optics, plasmas, etc., exhibits RWs only in the regime of modulation instability (MI) of the background. For a system of multiple waveguides, the governing coupled NLSEs can produce regimes of MI and RWs, even if each component has dispersion and cubic nonlinearity of opposite signs. A similar effect is demonstrated here for a system of coupled derivative NLSEs (DNLSEs) where the special feature is the nonlinear self-steepening of narrow pulses. More precisely, these additional regimes of MI and RWs for coupled DNLSEs depend on the mismatch in group velocities between the components, and the parameters for cubic nonlinearity and self-steepening. RWs considered in this paper differ from those of the NLSEs in terms of the amplification ratio and criteria of existence. Applications to optics and plasma physics are discussed.
Optomechanics: Vibrations copying optical chaos
NASA Astrophysics Data System (ADS)
Sciamanna, Marc
2016-06-01
Mechanical oscillation in a microtoroidal optical cavity transfers chaos from a pump to a probe laser beam with a different wavelength. Through stochastic resonance, the combination of noise and internal chaotic dynamics leads to amplification of optomechanically induced light self-oscillations.
Nonlinear Landau-Zener tunneling in coupled waveguide arrays
Khomeriki, Ramaz
2010-07-15
The possibility of direct observation of the nonlinear Landau-Zener tunneling effect with a device consisting of two waveguide arrays connected to a tilted reduced refractive index barrier is discussed. Numerical simulations on this realistic setup are interpreted via a simplified double-well system and different asymmetric tunneling scenarios are predicted varying just the injected beam intensity.
Strong optomechanical interactions in a sliced photonic crystal nanobeam
Leijssen, Rick; Verhagen, Ewold
2015-01-01
Coupling between mechanical and optical degrees of freedom is strongly enhanced by using subwavelength optical mode profiles. We realize an optomechanical system based on a sliced photonic crystal nanobeam, which combines such highly confined optical fields with a low-mass mechanical mode. Analyzing the transduction of motion and effects of radiation pressure we find the system exhibits a photon-phonon coupling rate g0 /2π ≈ 11.5 MHz, exceeding previously reported values by an order of magnitude. We show that the large optomechanical interaction enables detecting thermal motion with detection noise below that at the standard quantum limit, even in broad bandwidth devices, important for both sensor applications as well as measurement-based quantum control. PMID:26522751
Dynamic entanglement transfer in a double-cavity optomechanical system
NASA Astrophysics Data System (ADS)
Huan, Tiantian; Zhou, Rigui; Ian, Hou
2015-08-01
We give a theoretical study of a double-cavity system in which a mechanical resonator beam is coupled to two cavity modes on both sides through radiation pressures. The indirect coupling between the cavities via the resonator sets up a correlation in the optomechanical entanglements between the two cavities with the common resonator. This correlation initiates an entanglement transfer from the intracavity photon-phonon entanglements to an intercavity photon-photon entanglement. Using numerical solutions, we show two distinct regimes of the optomechanical system, in which the indirect entanglement either builds up and eventually saturates or undergoes a death-and-revival cycle, after a time lapse for initiating the cooperative motion of the left and right cavity modes.
Non-Linear Luminescent Coupling in Series-Connected Multijunction Solar Cells
Steiner, M. A.; Geisz, J. F.
2012-06-18
The assumption of superposition or linearity of photocurrent with solar flux is widespread for calculations and measurements of solar cells. The well-known effect of luminescent coupling in multijunction solar cells has also been assumed to be linear with excess current. Here we show significant non-linearities in luminescent coupling in III-V multijunction solar cells and propose a simple model based on competition between radiative and nonradiative processes in the luminescent junction to explain these non-linearities. We demonstrate a technique for accurately measuring the junction photocurrents under a specified reference spectrum, that accounts for and quantifies luminescent coupling effects.
Nano-optomechanical system based on microwave frequency surface acoustic waves
NASA Astrophysics Data System (ADS)
Tadesse, Semere Ayalew
Cavity optomechnics studies the interaction of cavity confined photons with mechanical motion. The emergence of sophisticated nanofabrication technology has led to experimental demonstrations of a wide range of novel optomechanical systems that exhibit strong optomechanical coupling and allow exploration of interesting physical phenomena. Many of the studies reported so far are focused on interaction of photons with localized mechanical modes. For my doctoral research, I did experimental investigations to extend this study to propagating phonons. I used surface travelling acoustic waves as the mechanical element of my optomechanical system. The optical cavities constitute an optical racetrack resonator and photonic crystal nanocavity. This dissertation discusses implementation of this surface acoustic wave based optomechanical system and experimental demonstrations of important consequences of the optomechanical coupling. The discussion focuses on three important achievements of the research. First, microwave frequency surface acoustic wave transducers were co-integrated with an optical racetrack resonator on a piezoelectric aluminum nitride film deposited on an oxidized silicon substrate. Acousto-optic modulation of the resonance modes at above 10 GHz with the acoustic wavelength significantly below the optical wavelength was achieved. The phase and modal matching conditions in this paradigm were investigated for efficient optmechanical coupling. Second, the optomechanical coupling was pushed further into the sideband resolved regime by integrating the high frequency surface acoustic wave transducers with a photonic crystal nanocavity. This device was used to demonstrate optomecahnically induced transparency and absorption, one of the interesting consequences of cavity optomechanics. Phase coherent interaction of the acoustic wave with multiple nanocavities was also explored. In a related experiment, the photonic crystal nanoscavity was placed inside an acoustic
NASA Astrophysics Data System (ADS)
Garai, S.; Janaki, M. S.; Chakrabarti, N.
2016-09-01
The nonlinear propagation of low frequency waves, in a collisionless, strongly coupled dusty plasma (SCDP) with a density dependent viscosity, has been studied with a proper Galilean invariant generalized hydrodynamic (GH) model. The well known reductive perturbation technique (RPT) has been employed in obtaining the solutions of the longitudinal and transverse perturbations. It has been found that the nonlinear propagation of the acoustic perturbations govern with the modified Korteweg-de Vries (KdV) equation and are decoupled from the sheared fluctuations. In the regions, where transversal gradients of the flow exists, coupling between the longitudinal and transverse perturbations occurs due to convective nonlinearity which is true for the homogeneous case also. The results, obtained here, can have relative significance to astrophysical context as well as in laboratory plasmas.
Opto-mechanical subsystem with temperature compensation through isothemal design
NASA Technical Reports Server (NTRS)
Goodwin, F. E. (Inventor)
1977-01-01
An opto-mechanical subsystem for supporting a laser structure which minimizes changes in the alignment of the laser optics in response to temperature variations is described. Both optical and mechanical structural components of the system are formed of the same material, preferably beryllium, which is selected for high mechanical strength and good thermal conducting qualities. All mechanical and optical components are mounted and assembled to provide thorough thermal coupling throughout the subsystem to prevent the development of temperature gradients.
Unitary qubit extremely parallelized algorithms for coupled nonlinear Schrodinger equations
NASA Astrophysics Data System (ADS)
Oganesov, Armen; Flint, Chris; Vahala, George; Vahala, Linda; Yepez, Jeffrey; Soe, Min
2015-11-01
The nonlinear Schrodinger equation (NLS) is a ubiquitous equation occurring in plasma physics, nonlinear optics and in Bose Einstein condensates. Viewed from the BEC standpoint of phase transitions, the wave function is the order parameter and topological defects in that manifold are simply the vortices, which for a scalar NLS have quantized circulation. In multi-species NLS the topological nature of the vortices are radically different with some classes of vortices no longer having quantized circulation as in classical turbulence. Moreover, some of the vortex equivalence classes need no longer be Abelian. This strongly effects the permitted vortex reconnections. The effect of these structures on the spectral properties of the ensuing turbulence will be investigated. Our 3D algorithm is based on a novel unitary qubit lattice scheme that is ideally parallelized - tested up to 780 000 cores on Mira. This scheme is mesoscopic (like lattice Boltzmann), but fully unitary (unlike LB). Supported by NSF, DoD.
Nonlinear motion of coupled magnetic vortices in ferromagnetic/non-magnetic/ferromagnetic trilayer
Jun, Su-Hyeong; Shim, Je-Ho; Oh, Suhk-Kun; Yu, Seong-Cho; Kim, Dong-Hyun; Mesler, Brooke; Fischer, Peter
2009-07-05
We have investigated a coupled motion of two vortex cores in ferromagnetic/nonmagnetic/ferromagnetic trilayer cynliders by means of micromagnetic simulation. Dynamic motion of two vortex with parallel and antiparallel relative chiralities of curling spins around the vortex cores have been examined after excitation by 1-ns pulsed external field. With systematic variation in non-magnetic spacer layer thickness from 0 to 20 nm, the coupling between two cores becomes significant as the spacer becomes thinner. Significant coupling leads to a nonlinear chaotic coupled motion of two vortex cores for the parallel chiralities and a faster coupled gyrotropic oscillation for the antiparallel chiralities.
Diabolical points in multi-scatterer optomechanical systems
Chesi, Stefano; Wang, Ying-Dan; Twamley, Jason
2015-01-01
Diabolical points, which originate from parameter-dependent accidental degeneracies of a system's energy levels, have played a fundamental role in the discovery of the Berry phase as well as in photonics (conical refraction), in chemical dynamics, and more recently in novel materials such as graphene, whose electronic band structure possess Dirac points. Here we discuss diabolical points in an optomechanical system formed by multiple scatterers in an optical cavity with periodic boundary conditions. Such configuration is close to experimental setups using micro-toroidal rings with indentations or near-field scatterers. We find that the optomechanical coupling is no longer an analytic function near the diabolical point and demonstrate the topological phase arising through the mechanical motion. Similar to a Fabry-Perot resonator, the optomechanical coupling can grow with the number of scatterers. We also introduce a minimal quantum model of a diabolical point, which establishes a connection to the motion of an arbitrary-spin particle in a 2D parabolic quantum dot with spin-orbit coupling. PMID:25588627
Amplification effects in optomechanics via weak measurements
NASA Astrophysics Data System (ADS)
Li, Gang; Wang, Tao; Song, He-Shan
2014-07-01
We revisit the scheme of single-photon weak-coupling optomechanics using postselection, proposed by Pepper, Ghobadi, Jeffrey, Simon, and Bouwmeester [Phys. Rev. Lett. 109, 023601 (2012), 10.1103/PhysRevLett.109.023601], by analyzing the exact solution of the dynamical evolution. Positive and negative amplification effects of the displacement of the mirror's position can be generated when the Kerr phase is considered. This effect occurs when the postselected state of the photon is orthogonal to the initial state, which cannot be explained by the usual weak measurement results. The amplification effect can be further modulated by a phase shifter, and the maximal displacement state can appear within a short evolution time.
Nonlinear tunneling of optical soliton in 3 coupled NLS equation with symbolic computation
NASA Astrophysics Data System (ADS)
Mani Rajan, M. S.; Mahalingam, A.; Uthayakumar, A.
2014-07-01
We investigated the soliton solution for N coupled nonlinear Schrödinger (CNLS) equations. These equations are coupled due to the cross-phase-modulation (CPM). Lax pair of this system is obtained via the Ablowitz-Kaup-Newell-Segur (AKNS) scheme and the corresponding Darboux transformation is constructed to derive the soliton solution. One and two soliton solutions are generated. Using two soliton solutions of 3 CNLS equation, nonlinear tunneling of soliton for both with and without exponential background has been discussed. Finally cascade compression of optical soliton through multi-nonlinear barrier has been discussed. The obtained results may have promising applications in all-optical devices based on optical solitons, study of soliton propagation in birefringence fiber systems and optical soliton with distributed dispersion and nonlinearity management.
Large cooperativity and microkelvin cooling with a three-dimensional optomechanical cavity
Yuan, Mingyun; Singh, Vibhor; Blanter, Yaroslav M.; Steele, Gary A.
2015-01-01
In cavity optomechanics, light is used to control mechanical motion. A central goal of the field is achieving single-photon strong coupling, which would enable the creation of quantum superposition states of motion. Reaching this limit requires significant improvements in optomechanical coupling and cavity coherence. Here we introduce an optomechanical architecture consisting of a silicon nitride membrane coupled to a three-dimensional superconducting microwave cavity. Exploiting their large quality factors, we achieve an optomechanical cooperativity of 146,000 and perform sideband cooling of the kilohertz-frequency membrane motion to 34±5 μK, the lowest mechanical mode temperature reported to date. The achieved cooling is limited only by classical noise of the signal generator, and should extend deep into the ground state with superconducting filters. Our results suggest that this realization of optomechanics has the potential to reach the regimes of ultra-large cooperativity and single-photon strong coupling, opening up a new generation of experiments. PMID:26450772
Large cooperativity and microkelvin cooling with a three-dimensional optomechanical cavity
NASA Astrophysics Data System (ADS)
Yuan, Mingyun; Singh, Vibhor; Blanter, Yaroslav M.; Steele, Gary A.
2015-10-01
In cavity optomechanics, light is used to control mechanical motion. A central goal of the field is achieving single-photon strong coupling, which would enable the creation of quantum superposition states of motion. Reaching this limit requires significant improvements in optomechanical coupling and cavity coherence. Here we introduce an optomechanical architecture consisting of a silicon nitride membrane coupled to a three-dimensional superconducting microwave cavity. Exploiting their large quality factors, we achieve an optomechanical cooperativity of 146,000 and perform sideband cooling of the kilohertz-frequency membrane motion to 34+/-5 μK, the lowest mechanical mode temperature reported to date. The achieved cooling is limited only by classical noise of the signal generator, and should extend deep into the ground state with superconducting filters. Our results suggest that this realization of optomechanics has the potential to reach the regimes of ultra-large cooperativity and single-photon strong coupling, opening up a new generation of experiments.
Large cooperativity and microkelvin cooling with a three-dimensional optomechanical cavity.
Yuan, Mingyun; Singh, Vibhor; Blanter, Yaroslav M; Steele, Gary A
2015-01-01
In cavity optomechanics, light is used to control mechanical motion. A central goal of the field is achieving single-photon strong coupling, which would enable the creation of quantum superposition states of motion. Reaching this limit requires significant improvements in optomechanical coupling and cavity coherence. Here we introduce an optomechanical architecture consisting of a silicon nitride membrane coupled to a three-dimensional superconducting microwave cavity. Exploiting their large quality factors, we achieve an optomechanical cooperativity of 146,000 and perform sideband cooling of the kilohertz-frequency membrane motion to 34±5 μK, the lowest mechanical mode temperature reported to date. The achieved cooling is limited only by classical noise of the signal generator, and should extend deep into the ground state with superconducting filters. Our results suggest that this realization of optomechanics has the potential to reach the regimes of ultra-large cooperativity and single-photon strong coupling, opening up a new generation of experiments. PMID:26450772
Quantum noise effects with Kerr-nonlinearity enhancement in coupled gain-loss waveguides
NASA Astrophysics Data System (ADS)
He, Bing; Yan, Shu-Bin; Wang, Jing; Xiao, Min
2015-05-01
It is generally difficult to study the dynamical properties of a quantum system with both inherent quantum noises and nonperturbative nonlinearity. Due to the possibly drastic intensity increase of an input coherent light in gain-loss waveguide couplers with parity-time (PT ) symmetry, the Kerr effect from a nonlinearity added into the system can be greatly enhanced and is expected to create macroscopic entangled states of the output light fields with huge photon numbers. Meanwhile, quantum noises also coexist with the amplification and dissipation of the light fields. Under the interplay between the quantum noises and nonlinearity, the quantum dynamical behaviors of the systems become rather complicated. However, the important quantum noise effects have been mostly neglected in previous studies about nonlinear PT -symmetric systems. Here we present a solution to this nonperturbative quantum nonlinear problem, showing the real-time evolution of the system observables. The enhanced Kerr nonlinearity is found to give rise to a previously unknown decoherence effect that is irrelevant to the quantum noises and imposes a limit on the emergence of macroscopic nonclassicality. In contrast to what happens in linear systems, the quantum noises exert significant impact on the system dynamics and can create nonclassical light field states in conjunction with the enhanced Kerr nonlinearity. This study on the noise involved in quantum nonlinear dynamics of coupled gain-loss waveguides can help to better understand the quantum noise effects in many nonlinear systems.
NASA Astrophysics Data System (ADS)
Driben, R.; Konotop, V. V.; Meier, T.
2016-03-01
Nonlinearity is the driving force for numerous important effects in nature typically showing transitions between different regimes, regular, chaotic or catastrophic behavior. Localized nonlinear modes have been the focus of intense research in areas such as fluid and gas dynamics, photonics, atomic and solid state physics etc. Due to the richness of the behavior of nonlinear systems and due to the severe numerical demands of accurate three-dimensional (3D) numerical simulations presently only little knowledge is available on the dynamics of complex nonlinear modes in 3D. Here, we investigate the dynamics of 3D non-coaxial matter wave vortices that are trapped in a parabolic potential and interact via a repulsive nonlinearity. Our numerical simulations demonstrate the existence of an unexpected and fascinating nonlinear regime that starts immediately when the nonlinearity is switched-on and is characterized by a smooth dynamics representing torque-free precession with nutations. The reported motion is proven to be robust regarding various effects such as the number of particles, dissipation and trap deformations and thus should be observable in suitably designed experiments. Since our theoretical approach, i.e., coupled nonlinear Schrödinger equations, is quite generic, we expect that the obtained novel dynamical behavior should also exist in other nonlinear systems.
Driben, R.; Konotop, V. V.; Meier, T.
2016-01-01
Nonlinearity is the driving force for numerous important effects in nature typically showing transitions between different regimes, regular, chaotic or catastrophic behavior. Localized nonlinear modes have been the focus of intense research in areas such as fluid and gas dynamics, photonics, atomic and solid state physics etc. Due to the richness of the behavior of nonlinear systems and due to the severe numerical demands of accurate three-dimensional (3D) numerical simulations presently only little knowledge is available on the dynamics of complex nonlinear modes in 3D. Here, we investigate the dynamics of 3D non-coaxial matter wave vortices that are trapped in a parabolic potential and interact via a repulsive nonlinearity. Our numerical simulations demonstrate the existence of an unexpected and fascinating nonlinear regime that starts immediately when the nonlinearity is switched-on and is characterized by a smooth dynamics representing torque-free precession with nutations. The reported motion is proven to be robust regarding various effects such as the number of particles, dissipation and trap deformations and thus should be observable in suitably designed experiments. Since our theoretical approach, i.e., coupled nonlinear Schrödinger equations, is quite generic, we expect that the obtained novel dynamical behavior should also exist in other nonlinear systems. PMID:26964759
Sukhorukov, Andrey A; Solntsev, Alexander S; Kruk, Sergey S; Neshev, Dragomir N; Kivshar, Yuri S
2014-02-01
We derive general coupled-mode equations describing the nonlinear interaction of electromagnetic modes in periodic media with loss and gain. Our approach is rigorously based on the Lorentz reciprocity theorem, and it can be applied to a broad range of metal-dielectric photonic structures, including plasmonic waveguides and metamaterials. We verify that our general results agree with the previous analysis of particular cases, and predict novel effects on self- and cross-phase modulation in multilayer nonlinear fishnet metamaterials. PMID:24487840
He, Li; Li, Huan; Li, Mo
2016-01-01
Photons carry linear momentum and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, whereas transfer of angular momentum induces optical torque. Optical forces including radiation pressure and gradient forces have long been used in optical tweezers and laser cooling. In nanophotonic devices, optical forces can be significantly enhanced, leading to unprecedented optomechanical effects in both classical and quantum regimes. In contrast, to date, the angular momentum of light and the optical torque effect have only been used in optical tweezers but remain unexplored in integrated photonics. We demonstrate the measurement of the spin angular momentum of photons propagating in a birefringent waveguide and the use of optical torque to actuate rotational motion of an optomechanical device. We show that the sign and magnitude of the optical torque are determined by the photon polarization states that are synthesized on the chip. Our study reveals the mechanical effect of photon’s polarization degree of freedom and demonstrates its control in integrated photonic devices. Exploiting optical torque and optomechanical interaction with photon angular momentum can lead to torsional cavity optomechanics and optomechanical photon spin-orbit coupling, as well as applications such as optomechanical gyroscopes and torsional magnetometry. PMID:27626072
He, Li; Li, Huan; Li, Mo
2016-09-01
Photons carry linear momentum and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, whereas transfer of angular momentum induces optical torque. Optical forces including radiation pressure and gradient forces have long been used in optical tweezers and laser cooling. In nanophotonic devices, optical forces can be significantly enhanced, leading to unprecedented optomechanical effects in both classical and quantum regimes. In contrast, to date, the angular momentum of light and the optical torque effect have only been used in optical tweezers but remain unexplored in integrated photonics. We demonstrate the measurement of the spin angular momentum of photons propagating in a birefringent waveguide and the use of optical torque to actuate rotational motion of an optomechanical device. We show that the sign and magnitude of the optical torque are determined by the photon polarization states that are synthesized on the chip. Our study reveals the mechanical effect of photon's polarization degree of freedom and demonstrates its control in integrated photonic devices. Exploiting optical torque and optomechanical interaction with photon angular momentum can lead to torsional cavity optomechanics and optomechanical photon spin-orbit coupling, as well as applications such as optomechanical gyroscopes and torsional magnetometry. PMID:27626072
Nonlinear forced response of electromechanical integrated toroidal drive to coupled excitation.
Xu, Lizhong; Wang, Fen
2012-01-01
The electric excitation and the parameter excitation from mesh stiffness fluctuation are analyzed. The forced response equations of the drive system to the coupled excitations are presented. For the exciting frequencies far from and near natural frequencies, the forced responses of the drive system to the coupled excitations are investigated. Results show that the nonlinear forced responses of the drive system to the coupled excitations change periodically and unsteadily; the time period of the nonlinear forced responses depends on the frequencies of the electric excitation, the mesh parameter excitation, and the nonlinear natural frequencies of the drive system; in order to improve the dynamics performance of the drive system, the frequencies of the electric excitations should not be taken as integral multiple of the mesh parameter exciting frequency. PMID:23251105
Nonlinear regime of the mode-coupling instability in 2D plasma crystals
NASA Astrophysics Data System (ADS)
Röcker, T. B.; Couëdel, L.; Zhdanov, S. K.; Nosenko, V.; Ivlev, A. V.; Thomas, H. M.; Morfill, G. E.
2014-05-01
The transition between linear and nonlinear regimes of the mode-coupling instability (MCI) operating in a monolayer plasma crystal is studied. The mode coupling is triggered at the centre of the crystal and a melting front is formed, which travels through the crystal. At the nonlinear stage, the mode coupling results in synchronisation of the particle motion and the kinetic temperature of the particles grows exponentially. After melting of the crystalline structure, the mean kinetic energy of the particles continued to grow further, preventing recrystallisation of the melted phase. The anomalous kinetic temperature obtained in the experiments could not be reproduced in simulations employing a simple point-like wake model. This shows that at the nonlinear stage of the MCI a more careful analysis is necessary.
Yang, Yuan; Solis-Escalante, Teodoro; Yao, Jun; Daffertshofer, Andreas; Schouten, Alfred C; van der Helm, Frans C T
2016-02-01
Interaction between distant neuronal populations is essential for communication within the nervous system and can occur as a highly nonlinear process. To better understand the functional role of neural interactions, it is important to quantify the nonlinear connectivity in the nervous system. We introduce a general approach to measure nonlinear connectivity through phase coupling: the multi-spectral phase coherence (MSPC). Using simulated data, we compare MSPC with existing phase coupling measures, namely n : m synchronization index and bi-phase locking value. MSPC provides a system description, including (i) the order of the nonlinearity, (ii) the direction of interaction, (iii) the time delay in the system, and both (iv) harmonic and (v) intermodulation coupling beyond the second order; which are only partly revealed by other methods. We apply MSPC to analyze data from a motor control experiment, where subjects performed isotonic wrist flexions while receiving movement perturbations. MSPC between the perturbation, EEG and EMG was calculated. Our results reveal directional nonlinear connectivity in the afferent and efferent pathways, as well as the time delay (43 ± 8 ms) between the perturbation and the brain response. In conclusion, MSPC is a novel approach capable to assess high-order nonlinear interaction and timing in the nervous system. PMID:26404514
NASA Astrophysics Data System (ADS)
Assis, Vladimir R. V.; Copelli, Mauro
2009-12-01
We study a modified version of the stochastic susceptible-infected-refractory-susceptible (SIRS) model by employing a nonlinear (exponential) reinforcement in the contagion rate and no diffusion. We run simulations for complete and random graphs as well as d -dimensional hypercubic lattices (for d=3,2,1 ). For weak nonlinearity, a continuous nonequilibrium phase transition between an absorbing and an active phase is obtained, such as in the usual stochastic SIRS model [Joo and Lebowitz, Phys. Rev. E 70, 036114 (2004)]. However, for strong nonlinearity, the nonequilibrium transition between the two phases can be discontinuous for d≥2 , which is confirmed by well-characterized hysteresis cycles and bistability. Analytical mean-field results correctly predict the overall structure of the phase diagram. Furthermore, contrary to what was observed in a model of phase-coupled stochastic oscillators with a similar nonlinearity in the coupling [Wood , Phys. Rev. Lett. 96, 145701 (2006)], we did not find a transition to a stable (partially) synchronized state in our nonlinearly pulse-coupled excitable elements. For long enough refractory times and high enough nonlinearity, however, the system can exhibit collective excitability and unstable stochastic oscillations.
Compressive sensing reconstruction of feed-forward connectivity in pulse-coupled nonlinear networks
NASA Astrophysics Data System (ADS)
Barranca, Victor J.; Zhou, Douglas; Cai, David
2016-06-01
Utilizing the sparsity ubiquitous in real-world network connectivity, we develop a theoretical framework for efficiently reconstructing sparse feed-forward connections in a pulse-coupled nonlinear network through its output activities. Using only a small ensemble of random inputs, we solve this inverse problem through the compressive sensing theory based on a hidden linear structure intrinsic to the nonlinear network dynamics. The accuracy of the reconstruction is further verified by the fact that complex inputs can be well recovered using the reconstructed connectivity. We expect this Rapid Communication provides a new perspective for understanding the structure-function relationship as well as compressive sensing principle in nonlinear network dynamics.
Optomechanical considerations for realistic tolerancing
NASA Astrophysics Data System (ADS)
Herman, Eric; Sasián, José; Youngworth, Richard N.
2013-09-01
Optical tolerancing simulation has improved so that the modeling of optomechanical accuracy can better predict as-built performance. A key refinement being proposed within this paper is monitoring formal interference fits and checking lens elements within their mechanical housings. Without proper checks, simulations may become physically unrealizable and pessimistic, thereby resulting in lower simulated yields. An improved simulation method has been defined and demonstrated in this paper with systems that do not have barrel constraints. The demonstration cases clearly show the trend of the beneficial impact with yield results, as a yield increase of 36.3% to 39.2% is garnered by one example. Considerations in simulating the realistic optomechanical system will assist in controlling cost and providing more accurate simulation results.
Weak nonlinear coupling of Rossby-Haurwitz waves
NASA Astrophysics Data System (ADS)
Becker, G.
1986-11-01
The Rossby-Haurwitz waves as solutions of the linearized free barotropic vorticity equation in a spherical coordinate system are in good agreement with the observed ultralong planetary waves of the troposphere. Within an antisymmetric basic flow, as in the middle atmosphere, the solutions become unstable because of mathematical singularities, called 'critical latitudes'. Therefore the nonlinear advection terms have to be considered in such a case. Analytical solutions of a corresponding spectral truncated model demonstrate the weak interaction between the mean flow and the ultralong waves of zonal wavenumbers one to three. The time structures of the planetary waves change from periodic oscillations via vacillations to turbulent character with increasing initial amplitudes. Finally the spectral model is extended by the waves of wavenumber four. The numerical solutions for the periods of the planetary waves within tropospheric and stratospheric basic flow configurations agree with observations.
Nonreciprocal wave scattering on nonlinear string-coupled oscillators
Lepri, Stefano; Pikovsky, Arkady
2014-12-01
We study scattering of a periodic wave in a string on two lumped oscillators attached to it. The equations can be represented as a driven (by the incident wave) dissipative (due to radiation losses) system of delay differential equations of neutral type. Nonlinearity of oscillators makes the scattering non-reciprocal: The same wave is transmitted differently in two directions. Periodic regimes of scattering are analyzed approximately, using amplitude equation approach. We show that this setup can act as a nonreciprocal modulator via Hopf bifurcations of the steady solutions. Numerical simulations of the full system reveal nontrivial regimes of quasiperiodic and chaotic scattering. Moreover, a regime of a “chaotic diode,” where transmission is periodic in one direction and chaotic in the opposite one, is reported.
Multifrequency synthesis using two coupled nonlinear oscillator arrays.
Palacios, Antonio; Carretero-González, Ricardo; Longhini, Patrick; Renz, Norbert; In, Visarath; Kho, Andy; Neff, Joseph D; Meadows, Brian K; Bulsara, Adi R
2005-08-01
We illustrate a scheme that exploits the theory of symmetry-breaking bifurcations for generating a spatio-temporal pattern in which one of two interconnected arrays, each with N Van der Pol oscillators, oscillates at N times the frequency of the other. A bifurcation analysis demonstrates that this type of frequency generation cannot be realized without the mutual interaction between the two arrays. It is also demonstrated that the mechanism for generating these frequencies between the two arrays is different from that of a master-slave interaction, a synchronization effect, or that of subharmonic and ultraharmonic solutions generated by forced systems. This kind of frequency generation scheme can find applications in the developed field of nonlinear antenna and radar systems. PMID:16196688
Nonlinear frequency coupling in dual radio-frequency driven atmospheric pressure plasmas
Waskoenig, J.; Gans, T.
2010-05-03
Plasma ionization, and associated mode transitions, in dual radio-frequency driven atmospheric pressure plasmas are governed through nonlinear frequency coupling in the dynamics of the plasma boundary sheath. Ionization in low-power mode is determined by the nonlinear coupling of electron heating and the momentary local plasma density. Ionization in high-power mode is driven by electron avalanches during phases of transient high electric fields within the boundary sheath. The transition between these distinctly different modes is controlled by the total voltage of both frequency components.
Combined solitons in generalized coupled mode equations of a nonlinear optical Bragg grating
Alatas, Husin
2007-08-15
We discuss the existence of combined dark and antidark soliton forms or combined solitons in the generalized coupled mode equations of a nonlinear optical Bragg grating. These solitons are not allowed in the conventional coupled mode equations with uniform nonlinearity and exist outside the linear grating band gap. Their related Hamiltonian phase portrait was briefly reported by de Sterke et al. [Phys. Rev. E 54, 1969 (1996)]. The explicit expressions for the corresponding solitons are presented, as well as their bifurcation process. We demonstrate the unstable propagation of perturbed combined solitons with zero velocity by means of direct numerical integration.
Oester, Michael; Johansson, Magnus
2005-02-01
We consider a lattice model for waveguide arrays embedded in nonlinear Kerr media. Inclusion of nonlinear coupling results in many phenomena involving complex, phase-twisted, stationary modes. The norm (Poynting power) current of stable plane-wave solutions can be controlled in magnitude and direction, and may be reversed without symmetry-breaking perturbations. Also stable localized phase-twisted modes with zero current exist, which for particular parameter values may be compact and expressed analytically. The model also describes coupled Bose-Einstein condensates.
Time-Resolved Nonlinear Coupling between Orthogonal Flexural Modes of a Pristine GaAs Nanowire.
Cadeddu, D; Braakman, F R; Tütüncüoglu, G; Matteini, F; Rüffer, D; Fontcuberta i Morral, A; Poggio, M
2016-02-10
We demonstrate nonlinear coupling between two orthogonal flexural modes of single as-grown GaAs nanowires. The resonant frequency of one mode can be shifted over many line widths by mechanically driving the other mode. We present time-domain measurements of the mode coupling and characterize it further by pump-probe experiments. Measurements show that a geometric nonlinearity causes the frequency of one mode to depend directly on the square amplitude of the other mode. Nearly degenerate orthogonal modes in nanowires are particularly interesting given their potential use in vectorial force sensing. PMID:26785132
A chip-scale integrated cavity-electro-optomechanics platform.
Winger, M; Blasius, T D; Mayer Alegre, T P; Safavi-Naeini, A H; Meenehan, S; Cohen, J; Stobbe, S; Painter, O
2011-12-01
We present an integrated optomechanical and electromechanical nanocavity, in which a common mechanical degree of freedom is coupled to an ultrahigh-Q photonic crystal defect cavity and an electrical circuit. The system allows for wide-range, fast electrical tuning of the optical nanocavity resonances, and for electrical control of optical radiation pressure back-action effects such as mechanical amplification (phonon lasing), cooling, and stiffening. These sort of integrated devices offer a new means to efficiently interconvert weak microwave and optical signals, and are expected to pave the way for a new class of micro-sensors utilizing optomechanical back-action for thermal noise reduction and low-noise optical read-out. PMID:22273884
Robust entanglement via optomechanical dark mode: adiabatic scheme
NASA Astrophysics Data System (ADS)
Tian, Lin; Wang, Ying-Dan; Huang, Sumei; Clerk, Aashish
2013-03-01
Entanglement is a powerful resource for studying quantum effects in macroscopic objects and for quantum information processing. Here, we show that robust entanglement between cavity modes with distinct frequencies can be generated via a mechanical dark mode in an optomechanical quantum interface. Due to quantum interference, the effect of the mechanical noise is cancelled in a way that is similar to the electromagnetically induced transparency. We derive the entanglement in the strong coupling regime by solving the quantum Langevin equation using a perturbation theory approach. The entanglement in the adiabatic scheme is then compared with the entanglement in the stationary state scheme. Given the robust entanglement schemes and our previous schemes on quantum wave length conversion, the optomechanical interface hence forms an effective building block for a quantum network. This work is supported by DARPA-ORCHID program, NSF-DMR-0956064, NSF-CCF-0916303, and NSF-COINS.
Optomechanical Entanglement Between an Ion and an Optical Cavity Field
NASA Astrophysics Data System (ADS)
Bhattacherjee, Aranya B.
2016-04-01
I study an optomechanical system in which the mechanical motion of a single trapped ion is coupled to a cavity field for the realization of a strongly quantum correlated two-mode system. I show that for large pump intensities the steady state photon number exhibits bistable behaviour. I further analyze the occurrence of normal mode splitting (NMS) due to mixing of the fluctuations of the cavity field and the fluctuations of the ion motion which indicates a coherent energy exchange. I also find that in the parameter regime where NMS exists, the steady state of the system shows continuous variable entanglement. Such a two-mode optomechanical system can be used for the realization of continuous variable quantum information interfaces and networks.
Optomechanical synchronization phenomena in the presence of (quantum) noise
NASA Astrophysics Data System (ADS)
Weiss, Talitha; Kronwald, Andreas; Walter, Stefan; Marquardt, Florian
Synchronization is a phenomenon that appears in various natural and man-made systems. Optomechanical limit-cycle oscillators can synchronize when they are coupled to each other or to an external periodic force. Classically, in the absence of noise, different synchronization regimes can be identified. Notably, optomechanical systems tend to synchronize either in-phase or anti-phase. We investigate how the synchronization behaviour is affected in the presence of the fundamental quantum noise (arXiv:1507.06190). We find a regime where fluctuations drive transitions between the classical synchronization states and explore the quantum-to-classical crossover. Finally, we compare the effects of quantum noise to the effects of thermal noise.
Cavity optomechanics and its applications
NASA Astrophysics Data System (ADS)
Bhattacharya, Mishkatul
2009-05-01
Cavity optomechanics is an emerging field at the intersection of quantum optics, atomic physics, nanoscience and gravitational wave interferometry. It involves cavities (with one or more mechanical degrees of freedom) driven by laser radiation. The ensuing optical control of macroscopic mechanical motion may have implications for precision sensing, coherent control of atoms and molecules, and quantum information processing. Due to recent innovations optomechanical physics has been realized in a variety of experimental systems spanning many orders of magnitude in mass and time-scales. In this talk, I will first introduce the basic paradigm of a laser-driven two mirror cavity used for cooling a vibrational mode. A three-mirror configuration recently implemented using a partially transmissive dielectric membrane in a high finesse cavity will then be discussed, and shown to be superior to the two-mirror design in a number of ways. One implication of the three-mirror configuration is the possibility of scaling optomechanical techniques to multiple oscillators. This topic will be explored by analysing the case of two membranes in a cavity where it will be shown that the collective(center-of-mass and breathing) modes of vibration can be cooled independently, analogous to a chain of trapped ions. Finally, future directions for possible applications to the control of atoms and molecules will be indicated briefly.
Existence of solutions for a Schrödinger system with linear and nonlinear couplings
NASA Astrophysics Data System (ADS)
Li, Kui; Zhang, Zhitao
2016-08-01
We study an important system of Schrödinger equations with linear and nonlinear couplings arising from Bose-Einstein condensates. We use the Nehari manifold to prove the existence of a ground state solution; moreover, we give the sign of the solutions depending on linear coupling; by using index theory and Nehari manifold, we prove that there exist infinitely many positive bound state solutions.
Properties of linear entropy of the atom in a tripartite cavity-optomechanical system
NASA Astrophysics Data System (ADS)
Liao, Q. H.; Nie, W. J.; Xu, J.; Liu, Y.; Zhou, N. R.; Yan, Q. R.; Chen, A.; Liu, N. H.; Ahmad, M. A.
2016-05-01
We investigate the dynamics of linear entropy of an atom in a tripartite cavity-optomechanical system consisting of a two-level atom in a high-finesse optical cavity with a vibrating mirror at one end. The influence of atomic coherence on the time evolution of linear entropy is examined. It is shown that a Greenberger–Horne–Zeilinger like state can be generated. Moreover, it is found that the entanglement between the atom and the subsystem of field and mirror can be controlled by atomic coherence and the parameters of optomechanical coupling coefficient and atom-field coupling strength.
Nonlinear tunneling of optical soliton in 3 coupled NLS equation with symbolic computation
Mani Rajan, M.S.; Mahalingam, A.; Uthayakumar, A.
2014-07-15
We investigated the soliton solution for N coupled nonlinear Schrödinger (CNLS) equations. These equations are coupled due to the cross-phase-modulation (CPM). Lax pair of this system is obtained via the Ablowitz–Kaup–Newell–Segur (AKNS) scheme and the corresponding Darboux transformation is constructed to derive the soliton solution. One and two soliton solutions are generated. Using two soliton solutions of 3 CNLS equation, nonlinear tunneling of soliton for both with and without exponential background has been discussed. Finally cascade compression of optical soliton through multi-nonlinear barrier has been discussed. The obtained results may have promising applications in all-optical devices based on optical solitons, study of soliton propagation in birefringence fiber systems and optical soliton with distributed dispersion and nonlinearity management. -- Highlights: •We consider the nonlinear tunneling of soliton in birefringence fiber. •3-coupled NLS (CNLS) equation with variable coefficients is considered. •Two soliton solutions are obtained via Darboux transformation using constructed Lax pair. •Soliton tunneling through dispersion barrier and well are investigated. •Finally, cascade compression of soliton has been achieved.
Predicting the phonon spectra of coupled nonlinear chains using effective phonon theory
NASA Astrophysics Data System (ADS)
Su, Ruixia; Yuan, Zongqiang; Wang, Jun; Zheng, Zhigang
2016-06-01
In general one-dimensional nonlinear lattices, extensive studies have discovered the existence of renormalized phonons due to nonlinear interactions and found these renormalized phonons, as the energy carriers, are responsible for heat transport. Within the framework of renormalized phonons, a generic form of renormalized phonon spectrum has been derived and effective phonon theory (EPT) has been developed to explain the heat transport in general 1D nonlinear lattices. Our attention is dedicated to generalizing the EPT for two-layer nonlinear lattices and deriving the analytic expression of phonon spectra. By calculating the phonon spectra of different coupled models with EPT, it is found that the phonon dispersion relation is in good agreement with the result obtained from the spectral energy density method. It is demonstrated that the EPT of a coupled system can predict the phonon spectra of two-layer nonlinear lattices well. Thus, this finding may shed light on the prediction of heat conduction behavior in a coupled system, qualitatively, and provide a useful guide for designing thermal devices.
Regular black holes in f (R ) gravity coupled to nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Rodrigues, Manuel E.; Junior, Ednaldo L. B.; Marques, Glauber T.; Zanchin, Vilson T.
2016-07-01
We obtain a class of regular black hole solutions in four-dimensional f (R ) gravity, R being the curvature scalar, coupled to a nonlinear electromagnetic source. The metric formalism is used and static spherically symmetric spacetimes are assumed. The resulting f (R ) and nonlinear electrodynamics functions are characterized by a one-parameter family of solutions which are generalizations of known regular black holes in general relativity coupled to nonlinear electrodynamics. The related regular black holes of general relativity are recovered when the free parameter vanishes, in which case one has f (R )∝R . We analyze the regularity of the solutions and also show that there are particular solutions that violate only the strong energy condition.
Ding, Yaqiong; Xue, Chunhua; Sun, Yong; Jiang, Haitao; Li, Yunhui; Li, Hongqiang; Chen, Hong
2012-10-22
We propose a scheme for subwavelength electromagnetic switch by employing nonlinear meta-atom. Bistable response is conceptually demonstrated on a microwave transmission line, which is side-coupled to a varactor-loaded split ring resonator acting as a nonlinear meta-atom. Calculations and experiments show that by applying conductive coupling instead of near-field interaction between the transmission line and the nonlinear meta-atom, switch performances are improved. The switch threshold of low to -5.8 dBm and the transmission contrast of up to 4.0 dB between the two bistable states were achieved. Subwavelength size of our switch should be useful for miniaturization of integrated optical nanocircuits. PMID:23187246
Exact Solutions for N-Coupled Nonlinear Schrödinger Equations With Variable Coefficients
NASA Astrophysics Data System (ADS)
Tang, Bo; Fan, Yingzhe; Wang, Jixiu; Chen, Shijun
2016-07-01
In this paper, based on similarity transformation and auxiliary equation method, we construct many exact solutions of N-coupled nonlinear Schrödinger equations with variable coefficients, which include soliton solutions, combined soliton solutions, triangular periodic solutions, Jacobi elliptic function solutions and combined Jacobi elliptic function solutions. These solutions may give insight into many considerable physical processes.
Nonreciprocal conversion between microwave and optical photons in electro-optomechanical systems
NASA Astrophysics Data System (ADS)
Xu, Xun-Wei; Li, Yong; Chen, Ai-Xi; Liu, Yu-xi
2016-02-01
We propose to demonstrate nonreciprocal conversion between microwave and optical photons in an electro-optomechanical system where a microwave mode and an optical mode are coupled indirectly via two nondegenerate mechanical modes. The nonreciprocal conversion is obtained in the broken time-reversal symmetry regime, where the conversion of photons from one frequency to the other is enhanced for constructive quantum interference while the conversion in the reversal direction is suppressed due to destructive quantum interference. It is interesting that the nonreciprocal response between the microwave and optical modes in the electro-optomechanical system appears at two different frequencies with opposite directions. The proposal can be used to realize nonreciprocal conversion between photons of any two distinctive modes with different frequencies. Moreover, the electro-optomechanical system can also be used to construct a three-port circulator for three optical modes with distinctively different frequencies by adding an auxiliary optical mode coupled to one of the mechanical modes.
NASA Astrophysics Data System (ADS)
Irving, A. D.; Dewson, T.
1997-02-01
A new method is described for extracting mixed linear-nonlinear coupled differential equations from multivariate discrete time series data. It is assumed in the present work that the solution of the coupled ordinary differential equations can be represented as a multivariate Volterra functional expansion. A tractable hierarchy of moment equations is generated by operating on a suitably truncated Volterra functional expansion. The hierarchy facilitates the calculation of the coefficients of the coupled differential equations. In order to demonstrate the method's ability to accurately estimate the coefficients of the governing differential equations, it is applied to data derived from the numerical solution of the Lorenz equations with additive noise. The method is then used to construct a dynamic global mid- and high-magnetic latitude ionospheric model where nonlinear phenomena such as period doubling and quenching occur. It is shown that the estimated inhomogeneous coupled second-order differential equation model for the ionospheric foF2 peak plasma density can accurately forecast the future behaviour of a set of ionosonde stations which encompass the earth. Finally, the method is used to forecast the future behaviour of a portfolio of Japanese common stock prices. The hierarchy method can be used to characterise the observed behaviour of a wide class of coupled linear and mixed linear-nonlinear phenomena.
Tackling excess noise from bilinear and nonlinear couplings in gravitational-wave interferometers
NASA Astrophysics Data System (ADS)
Bose, Sukanta; Hall, Bernard; Mazumder, Nairwita; Dhurandhar, Sanjeev; Gupta, Anuradha; Lundgren, Andrew
2016-05-01
We describe a tool we improved to detect excess noise in the gravitational wave (GW) channel arising from its bilinear or nonlinear coupling with fluctuations of various components of a GW interferometer and its environment. We also describe a higher-order statistics tool we developed to characterize these couplings, e.g., by unraveling the frequencies of the fluctuations contributing to such noise, and demonstrate its utility by applying it to understand nonlinear couplings in Advanced LIGO engineering data. Once such noise is detected, it is highly desirable to remove it or correct for it. Such action in the past has been shown to improve the sensitivity of the instrument in searches of astrophysical signals. If this is not possible, then steps must be taken to mitigate its influence, e.g., by characterizing its effect on astrophysical searches. We illustrate this through a study of the effect of transient sine-Gaussian noise artifacts on a compact binary coalescence template bank.
Beating polymer gels coupled with a nonlinear chemical reaction
NASA Astrophysics Data System (ADS)
Yoshida, Ryo; Kokufuta, Etsuo; Yamaguchi, Tomohiko
1999-06-01
We report on a beating polymer gel that exhibits periodical volume changes (swelling and deswelling) in a closed solution without external stimuli, like autonomous heartbeat. The mechanical oscillation is driven by the chemical energy of the oscillatory Belousov-Zhabotinsky (BZ) reaction. The gel is a copolymer gel of N-isopropylacrylamide (NIPAAm) in which ruthenium tris(2,2'-bipyridine) [Ru(bpy)3], known as a catalyst of the BZ reaction, is covalently bonded to the polymer chain. The poly[NIPAAm-co-Ru(bpy)3] gel provides an open system where the BZ reaction proceeds, when immersed in an aqueous solution containing the reactants of the BZ reaction (with the exception of a catalyst). The chemical oscillation in the BZ reaction generates the periodical changes of the charge of Ru(bpy)3 in the gel network between reduced [Ru(II)] and oxidized [Ru(III)] states. The gel swells at the oxidized state because the hydrophilicity of the polymer chains increases, while at the reduced state the gel deswells. Thus, the chemical energy is transduced into the mechanical energy to drive the polymer gel oscillation with a period of about 5 min, depending on the composition of the surrounding solution. The oscillation mode of the gel depends on its size scaled by the wavelength of the BZ pattern. Sufficiently small bead-like gels demonstrate isotropic beating. A large rectangular gel shows mechanical oscillation with a peristaltic motion coupled with the propagating chemical waves. The dynamic behavior of the chemical and mechanical oscillations have been analyzed with a model simulation.
Rogue waves for a system of coupled derivative nonlinear Schrödinger equations
NASA Astrophysics Data System (ADS)
Chan, Hiu Ning; Malomed, Boris; Chow, Kwok Wing
2015-11-01
Previous works in the literature on water waves have demonstrated that the fourth-order evolution of gravity waves in deep water will be governed by a higher order nonlinear Schrödinger equation. In the presence of two wave trains, the system is described by a higher order coupled nonlinear Schrödinger system. Through a gauge transformation, these evolution equations are reduced to a coupled derivative nonlinear Schrödinger system. The goal here is to study rogue waves, unexpectedly large displacements from an equilibrium position, through the Hirota bilinear transformation theoretically. The connections between the onset of rogue waves and modulation instability are investigated. The range of cubic nonlinearity allowing rogue wave formation is elucidated. Under a finite group velocity mismatch between the two components, the existence regime for rogue waves is extended as compared to the case with a single wave train. The amplification ratio of the amplitude can be higher than that of the single component nonlinear Schrödinger equation. Partial financial support has been provided by the Research Grants Council through contracts HKU711713E and HKU17200815.
Zhang, Da-Guang; Li, Meng-Han; Zhou, Hao-Miao
2015-10-15
For magnetostrictive rods under combined axial pre-stress and magnetic field, a general one-dimension nonlinear magneto-elastic coupled constitutive model was built in this paper. First, the elastic Gibbs free energy was expanded into polynomial, and the relationship between stress and strain and the relationship between magnetization and magnetic field with the polynomial form were obtained with the help of thermodynamic relations. Then according to microscopic magneto-elastic coupling mechanism and some physical facts of magnetostrictive materials, a nonlinear magneto-elastic constitutive with concise form was obtained when the relations of nonlinear strain and magnetization in the polynomial constitutive were instead with transcendental functions. The comparisons between the prediction and the experimental data of different magnetostrictive materials, such as Terfenol-D, Metglas and Ni showed that the predicted magnetostrictive strain and magnetization curves were consistent with experimental results under different pre-stresses whether in the region of low and moderate field or high field. Moreover, the model can fully reflect the nonlinear magneto-mechanical coupling characteristics between magnetic, magnetostriction and elasticity, and it can effectively predict the changes of material parameters with pre-stress and bias field, which is useful in practical applications.
Synchronization in an optomechanical cavity.
Shlomi, Keren; Yuvaraj, D; Baskin, Ilya; Suchoi, Oren; Winik, Roni; Buks, Eyal
2015-03-01
We study self-excited oscillations (SEO) in an on-fiber optomechanical cavity. Synchronization is observed when the optical power that is injected into the cavity is periodically modulated. A theoretical analysis based on the Fokker-Planck equation evaluates the expected phase space distribution (PSD) of the self-oscillating mechanical resonator. A tomography technique is employed for extracting PSD from the measured reflected optical power. Time-resolved state tomography measurements are performed to study phase diffusion and phase locking of the SEO. The detuning region inside which synchronization occurs is experimentally determined and the results are compared with the theoretical prediction. PMID:25871175
Instability and dynamics of two nonlinearly coupled intense laser beams in a quantum plasma
Wang Yunliang; Shukla, P. K.; Eliasson, B.
2013-01-15
We consider nonlinear interactions between two relativistically strong laser beams and a quantum plasma composed of degenerate electron fluids and immobile ions. The collective behavior of degenerate electrons is modeled by quantum hydrodynamic equations composed of the electron continuity, quantum electron momentum (QEM) equation, as well as the Poisson and Maxwell equations. The QEM equation accounts the quantum statistical electron pressure, the quantum electron recoil due to electron tunneling through the quantum Bohm potential, electron-exchange, and electron-correlation effects caused by electron spin, and relativistic ponderomotive forces (RPFs) of two circularly polarized electromagnetic (CPEM) beams. The dynamics of the latter are governed by nonlinear wave equations that include nonlinear currents arising from the relativistic electron mass increase in the CPEM wave fields, as well as from the beating of the electron quiver velocity and electron density variations reinforced by the RPFs of the two CPEM waves. Furthermore, nonlinear electron density variations associated with the driven (by the RPFs) quantum electron plasma oscillations obey a coupled nonlinear Schroedinger and Poisson equations. The nonlinearly coupled equations for our purposes are then used to obtain a general dispersion relation (GDR) for studying the parametric instabilities and the localization of CPEM wave packets in a quantum plasma. Numerical analyses of the GDR reveal that the growth rate of a fastest growing parametrically unstable mode is in agreement with the result that has been deduced from numerical simulations of the governing nonlinear equations. Explicit numerical results for two-dimensional (2D) localized CPEM wave packets at nanoscales are also presented. Possible applications of our investigation to intense laser-solid density compressed plasma experiments are highlighted.
Non-linear Frequency Shifts, Mode Couplings, and Decay Instability of Plasma Waves
NASA Astrophysics Data System (ADS)
Affolter, Mathew; Anderegg, F.; Driscoll, C. F.; Valentini, F.
2015-11-01
We present experiments and theory for non-linear plasma wave decay to longer wavelengths, in both the oscillatory coupling and exponential decay regimes. The experiments are conducted on non-neutral plasmas in cylindrical Penning-Malmberg traps, θ-symmetric standing plasma waves have near acoustic dispersion ω (kz) ~kz - αkz2 , discretized by kz =mz (π /Lp) . Large amplitude waves exhibit non-linear frequency shifts δf / f ~A2 and Fourier harmonic content, both of which are increased as the plasma dispersion is reduced. Non-linear coupling rates are measured between large amplitude mz = 2 waves and small amplitude mz = 1 waves, which have a small detuning Δω = 2ω1 -ω2 . At small excitation amplitudes, this detuning causes the mz = 1 mode amplitude to ``bounce'' at rate Δω , with amplitude excursions ΔA1 ~ δn2 /n0 consistent with cold fluid theory and Vlasov simulations. At larger excitation amplitudes, where the non-linear coupling exceeds the dispersion, phase-locked exponential growth of the mz = 1 mode is observed, in qualitative agreement with simple 3-wave instability theory. However, significant variations are observed experimentally, and N-wave theory gives stunningly divergent predictions that depend sensitively on the dispersion-moderated harmonic content. Measurements on higher temperature Langmuir waves and the unusual ``EAW'' (KEEN) waves are being conducted to investigate the effects of wave-particle kinetics on the non-linear coupling rates. Department of Energy Grants DE-SC0002451and DE-SC0008693.
Nonlinear time dependence of dark current in charge-coupled devices
NASA Astrophysics Data System (ADS)
Dunlap, Justin C.; Bodegom, Erik; Widenhorn, Ralf
2011-03-01
It is generally assumed that charge-coupled device (CCD) imagers produce a linear response of dark current versus exposure time except near saturation. We found a large number of pixels with nonlinear dark current response to exposure time to be present in two scientific CCD imagers. These pixels are found to exhibit distinguishable behavior with other analogous pixels and therefore can be characterized in groupings. Data from two Kodak CCD sensors are presented for exposure times from a few seconds up to two hours. Linear behavior is traditionally taken for granted when carrying out dark current correction and as a result, pixels with nonlinear behavior will be corrected inaccurately.
Kerr-lens-mediated dynamics of two nonlinearly coupled mode-locked laser oscillators
NASA Astrophysics Data System (ADS)
Wu, Song; Smith, Sandra L.; Fork, Richard L.
1992-02-01
The dynamics of two nonlinearly coupled femtosecond oscillators are investigated for the case where two distinct nonlinear mechanisms are balanced to determine the temporal relationship and properties of the pulses in the two oscillators. In the time domain the shared bleaching of a common absorber creates an attractive mechanism for the pulses, while interactive Kerr lens deflections create a repulsive mechanism. The interplay of these two mechanisms causes a variety of dynamical behaviors, including pulse synchronization, pulse duration switching, and a latching type of amplitude bistability.
Donko, Z.; Schulze, J.; Czarnetzki, U.; Luggenhoelscher, D.
2009-03-30
At low pressures, nonlinear self-excited plasma series resonance (PSR) oscillations are known to drastically enhance electron heating in geometrically asymmetric capacitively coupled radio frequency discharges by nonlinear electron resonance heating (NERH). Here we demonstrate via particle-in-cell simulations that high-frequency PSR oscillations can also be excited in geometrically symmetric discharges if the driving voltage waveform makes the discharge electrically asymmetric. This can be achieved by a dual-frequency (f+2f) excitation, when PSR oscillations and NERH are turned on and off depending on the electrical discharge asymmetry, controlled by the phase difference of the driving frequencies.
Low-power all-optical tunable plasmonic-mode coupling in nonlinear metamaterials
Zhang, Fan; Yang, Hong; Hu, Xiaoyong E-mail: qhgong@pku.edu.cn; Gong, Qihuang E-mail: qhgong@pku.edu.cn
2014-03-31
All-optical tunable plasmonic-mode coupling is realized in a nonlinear photonic metamaterial consisting of periodic arrays of gold asymmetrically split ring resonators, covered with a poly[(methyl methacrylate)-co-(disperse red 13 acrylate)] azobenzene polymer layer. The third-order optical nonlinearity of the azobenzene polymer is enormously enhanced by using resonant excitation. Under excitation with a 17-kW/cm{sup 2}, 532-nm pump light, plasmonic modes shift by 51 nm and the mode interval is enlarged by 30 nm. Compared with previous reports, the threshold pump intensity is reduced by five orders of magnitude, while extremely large tunability is maintained.
Nonlinear mode coupling theory of the lower-hybrid-drift instability
NASA Technical Reports Server (NTRS)
Drake, J. F.; Guzdar, P. N.; Hassam, A. B.; Huba, J. D.
1984-01-01
A nonlinear mode coupling theory of the lower-hybrid-drift instability is presented. A two-dimensional nonlinear wave equation is derived which describes lower-hybrid drift wave turbulence in the plane transverse to B (k.B = 0), and which is valid for finite beta, collisional and collisionless plasmas. The instability saturates by transferring energy from growing, long wavelength modes to damped, short wavelength modes. Detailed numerical results are presented which compare favorably to both recent computer simulations and experimental observations. Applications of this theory to space plasmas, the earth's magnetotail and the equatorial F region ionosphere, are discussed. Previously announced in STAR as N84-17734
Optomechanics with microwave light
NASA Astrophysics Data System (ADS)
Lehnert, Konrad
2009-03-01
Recently, superconducting circuits resonant at microwave frequencies have revolutionized the measurement of astrophysical detectors [1] and superconducting qubits [2]. In this talk, I will describe how we extend this technique to measuring and manipulating nanomechanical oscillators. By strongly coupling the motion of a nanomechanical oscillator to the resonance of the microwave circuit we create structures where the dominant dissipative force acting on the oscillator is the radiation pressure of microwave ``light'' [3]. These devices are ultrasensitive force detectors and they allow us to cool the oscillator towards its motional ground state. [4pt] [1] P. K. Day et al., Nature 425, 817 (2003).[0pt] [2] A. Wallraff et al., Nature 431, 162 (2004).[0pt] [3] J. D. Teufel, J. W. Harlow, C. A. Regal and K. W. Lehnert, Phys. Rev. Lett., 101, 197203 (2008).
Lasing from active optomechanical resonators
Czerniuk, T.; Brüggemann, C.; Tepper, J.; Brodbeck, S.; Schneider, C.; Kamp, M.; Höfling, S.; Glavin, B. A.; Yakovlev, D. R.; Akimov, A. V.; Bayer, M.
2014-01-01
Planar microcavities with distributed Bragg reflectors (DBRs) host, besides confined optical modes, also mechanical resonances due to stop bands in the phonon dispersion relation of the DBRs. These resonances have frequencies in the 10- to 100-GHz range, depending on the resonator’s optical wavelength, with quality factors exceeding 1,000. The interaction of photons and phonons in such optomechanical systems can be drastically enhanced, opening a new route towards the manipulation of light. Here we implemented active semiconducting layers into the microcavity to obtain a vertical-cavity surface-emitting laser (VCSEL). Thereby, three resonant excitations—photons, phonons and electrons—can interact strongly with each other providing modulation of the VCSEL laser emission: a picosecond strain pulse injected into the VCSEL excites long-living mechanical resonances therein. As a result, modulation of the lasing intensity at frequencies up to 40 GHz is observed. From these findings, prospective applications of active optomechanical resonators integrated into nanophotonic circuits may emerge. PMID:25008784
Lasing from active optomechanical resonators.
Czerniuk, T; Brüggemann, C; Tepper, J; Brodbeck, S; Schneider, C; Kamp, M; Höfling, S; Glavin, B A; Yakovlev, D R; Akimov, A V; Bayer, M
2014-01-01
Planar microcavities with distributed Bragg reflectors (DBRs) host, besides confined optical modes, also mechanical resonances due to stop bands in the phonon dispersion relation of the DBRs. These resonances have frequencies in the 10- to 100-GHz range, depending on the resonator's optical wavelength, with quality factors exceeding 1,000. The interaction of photons and phonons in such optomechanical systems can be drastically enhanced, opening a new route towards the manipulation of light. Here we implemented active semiconducting layers into the microcavity to obtain a vertical-cavity surface-emitting laser (VCSEL). Thereby, three resonant excitations--photons, phonons and electrons--can interact strongly with each other providing modulation of the VCSEL laser emission: a picosecond strain pulse injected into the VCSEL excites long-living mechanical resonances therein. As a result, modulation of the lasing intensity at frequencies up to 40 GHz is observed. From these findings, prospective applications of active optomechanical resonators integrated into nanophotonic circuits may emerge. PMID:25008784
NASA Astrophysics Data System (ADS)
Williams, Timothy C.; Shaddix, Christopher R.
2007-12-01
Intensified charge-coupled devices (ICCDs) are used extensively in many scientific and engineering environments to image weak or temporally short optical events. Care has to be taken in interpreting the images from ICCDs if quantitative results are required. In particular, nonuniform gain (flat field) and nonlinear response effects must be properly accounted for. Traditional flat-field corrections can only be applied in the linear regime of the ICCD camera, which limits the usable dynamic range. This paper reports a more general approach to image correction whereby the nonlinear gain response of each pixel of the ICCD is characterized over the full dynamic range of the camera. Image data can then be corrected for the combined effects of nonuniform gain and nonlinearity. The results from a two-color pyrometry measurement of soot field temperature are used to illustrate the capabilities of the new correction approach.
NASA Astrophysics Data System (ADS)
Zhang, Yaoyu; Xiao, Yanyang; Zhou, Douglas; Cai, David
2016-04-01
The Granger causality (GC) analysis is an effective approach to infer causal relations for time series. However, for data obtained by uniform sampling (i.e., with an equal sampling time interval), it is known that GC can yield unreliable causal inference due to aliasing if the sampling rate is not sufficiently high. To solve this unreliability issue, we consider the nonuniform sampling scheme as it can mitigate against aliasing. By developing an unbiased estimation of power spectral density of nonuniformly sampled time series, we establish a framework of spectrum-based nonparametric GC analysis. Applying this framework to a general class of pulse-coupled nonlinear networks and utilizing some particular spectral structure possessed by these nonlinear network data, we demonstrate that, for such nonlinear networks with nonuniformly sampled data, reliable GC inference can be achieved at a low nonuniform mean sampling rate at which the traditional uniform sampling GC may lead to spurious causal inference.
Generating large steady-state optomechanical entanglement by the action of Casimir force
NASA Astrophysics Data System (ADS)
Nie, WenJie; Lan, YueHeng; Li, Yong; Zhu, ShiYao
2014-12-01
In this paper, we study an optomechanical device consisting of a Fabry-Pérot cavity with two dielectric nanospheres trapped near the cavity mirrors by an external driving laser. In the condition where the distances between the nanospheres and cavity mirrors are small enough, the Casimir force helps the optomechanical coupling to induce a steady-state optomechanical entanglement of the mechanical and optical modes in a certain regime of parameters. We investigate in detail the dependence of the steady-state optomechanical entanglement on external control parameters of the system, i.e., the effective detuning, the pump powers of the cavity, the cavity decay rate and the wavelength of the driving field. It is found that the large steady-state optomechanical entanglement, i.e. E N = 5.76, can be generated with experimentally feasible parameters, i.e. the pump power P = 18.2 μW, the cavity decay rate κ = 0.5 MHz and the wavelength of the laser λ L=1064 nm, which should be checked by optical measurement.
An integrated low phase noise radiation-pressure-driven optomechanical oscillator chipset
Luan, Xingsheng; Huang, Yongjun; Li, Ying; McMillan, James F.; Zheng, Jiangjun; Huang, Shu-Wei; Hsieh, Pin-Chun; Gu, Tingyi; Wang, Di; Hati, Archita; Howe, David A.; Wen, Guangjun; Yu, Mingbin; Lo, Guoqiang; Kwong, Dim-Lee; Wong, Chee Wei
2014-01-01
High-quality frequency references are the cornerstones in position, navigation and timing applications of both scientific and commercial domains. Optomechanical oscillators, with direct coupling to continuous-wave light and non-material-limited f × Q product, are long regarded as a potential platform for frequency reference in radio-frequency-photonic architectures. However, one major challenge is the compatibility with standard CMOS fabrication processes while maintaining optomechanical high quality performance. Here we demonstrate the monolithic integration of photonic crystal optomechanical oscillators and on-chip high speed Ge detectors based on the silicon CMOS platform. With the generation of both high harmonics (up to 59th order) and subharmonics (down to 1/4), our chipset provides multiple frequency tones for applications in both frequency multipliers and dividers. The phase noise is measured down to −125 dBc/Hz at 10 kHz offset at ~400 μW dropped-in powers, one of the lowest noise optomechanical oscillators to date and in room-temperature and atmospheric non-vacuum operating conditions. These characteristics enable optomechanical oscillators as a frequency reference platform for radio-frequency-photonic information processing. PMID:25354711
NASA Astrophysics Data System (ADS)
Kanna, T.; Vijayajayanthi, M.; Lakshmanan, M.
2007-07-01
The bright soliton solutions of the mixed coupled nonlinear Schrödinger equations with two components (2-CNLS) with linear self- and cross-coupling terms have been obtained by identifying a transformation that transforms the corresponding equation to the integrable mixed 2-CNLS equations. The study on the collision dynamics of bright solitons shows that there exists periodic energy switching, due to the coupling terms. This periodic energy switching can be controlled by the new type of shape changing collisions of bright solitons arising in a mixed 2-CNLS system, characterized by intensity redistribution, amplitude dependent phase shift, and relative separation distance. We also point out that this system exhibits large periodic intensity switching even with very small linear self-coupling strengths.
NASA Astrophysics Data System (ADS)
Wang, Xiaodan; Wang, Yunliang; Liu, Tielu; Zhang, Fan
2016-06-01
> Two-dimensional nonlinear magnetosonic solitary and shock waves propagating perpendicular to the applied magnetic field are presented in quantum electron-positron-ion plasmas with strongly coupled classical ions and weakly coupled quantum electrons and positrons. The generalized viscoelastic hydrodynamic model is used for the ions and a quantum hydrodynamic model is introduced for the electrons and positrons. In the weakly nonlinear limit, a modified Kadomstev-Petviashvili (KP) equation with a damping term and a KP-Burgers equation have been derived in the kinetic regime and hydrodynamic regime, respectively. The analytical and numerical solutions of the modified KP and KP-Burgers equations are also presented and analysed with the typical parameters of a white dwarf star and pulsar magnetosphere, which show that the quantum plasma beta and the variation of positron number density have remarkable effects on the propagation of magnetosonic solitary and shock waves.
Spurious cross-frequency amplitude-amplitude coupling in nonstationary, nonlinear signals
NASA Astrophysics Data System (ADS)
Yeh, Chien-Hung; Lo, Men-Tzung; Hu, Kun
2016-07-01
Recent studies of brain activities show that cross-frequency coupling (CFC) plays an important role in memory and learning. Many measures have been proposed to investigate the CFC phenomenon, including the correlation between the amplitude envelopes of two brain waves at different frequencies - cross-frequency amplitude-amplitude coupling (AAC). In this short communication, we describe how nonstationary, nonlinear oscillatory signals may produce spurious cross-frequency AAC. Utilizing the empirical mode decomposition, we also propose a new method for assessment of AAC that can potentially reduce the effects of nonlinearity and nonstationarity and, thus, help to avoid the detection of artificial AACs. We compare the performances of this new method and the traditional Fourier-based AAC method. We also discuss the strategies to identify potential spurious AACs.
An experimental study on synchronization of nonlinear oscillators with Huygens' coupling
NASA Astrophysics Data System (ADS)
Peña-Ramírez, J.; Fey, R. H. B.; Nijmeijer, H.
In this experimental study, phase synchronization is studied in pairs of nonlinear oscillators coupled through a movable support. In particular, the dynamics of two discontinuous mass-spring-damper oscillators and the dynamics of the classical Huygens' pendulum clocks are considered. In both systems the individual oscillators are self-sustained. It is shown that in both cases, the oscillators exhibit in-phase and anti-phase synchronization. All experiments are executed on a new experimental setup consisting of two controllable mass-spring-damper oscillators coupled through an elastically supported rigid bar. The results suggest, that the synchronized motion observed by Christiaan Huygens around 1650 in a pair of pendulum clocks mounted on a flexible support, in many cases can also be observed when the pendulum clocks are replaced by other self-sustained nonlinear oscillators.
Nonlinear mode coupling and synchronization of a vacuum-trapped nanoparticle.
Gieseler, Jan; Spasenović, Marko; Novotny, Lukas; Quidant, Romain
2014-03-14
We study the dynamics of a laser-trapped nanoparticle in high vacuum. Using parametric coupling to an external excitation source, the linewidth of the nanoparticle's oscillation can be reduced by three orders of magnitude. We show that the oscillation of the nanoparticle and the excitation source are synchronized, exhibiting a well-defined phase relationship. Furthermore, the external source can be used to controllably drive the nanoparticle into the nonlinear regime, thereby generating strong coupling between the different translational modes of the nanoparticle. Our work contributes to the understanding of the nonlinear dynamics of levitated nanoparticles in high vacuum and paves the way for studies of pattern formation, chaos, and stochastic resonance. PMID:24679293
NASA Technical Reports Server (NTRS)
Keskinen, M. J.; Satyanarayana, P.
1993-01-01
The nonlinear evolution of thermospheric winds in an ionosphere-magnetosphere coupled model has been studied for the first time for a dynamic unstable auroral-arc environment. We treat the problem using a multi-layer, quasi-three-dimensional model which averages in altitude the thermospheric dynamics over each layer. For the upper thermosphere, we find that (1) the thermosphere can respond to the ionospheric Kelvin-Helmholtz (KH) instability on temporal scales on the order of an hour, depending on ambient conditions, and on spatial scales of tens to hundreds of kilometers, (2) strong thermospheric meridional and zonal vortical flows with embedded nonlinear jet-like structures can be generated by the ionospheric/magnetospheric KH instability and (3) neutral thermospheric winds, vortices, and associated power spectra develop in a distinctly different manner in the presence of magnetospheric coupling effects. Comparison with recent observations is made.
Bifurcation and chaos analysis of a nonlinear electromechanical coupling relative rotation system
NASA Astrophysics Data System (ADS)
Liu, Shuang; Zhao, Shuang-Shuang; Sun, Bao-Ping; Zhang, Wen-Ming
2014-09-01
Hopf bifurcation and chaos of a nonlinear electromechanical coupling relative rotation system are studied in this paper. Considering the energy in air-gap field of AC motor, the dynamical equation of nonlinear electromechanical coupling relative rotation system is deduced by using the dissipation Lagrange equation. Choosing the electromagnetic stiffness as a bifurcation parameter, the necessary and sufficient conditions of Hopf bifurcation are given, and the bifurcation characteristics are studied. The mechanism and conditions of system parameters for chaotic motions are investigated rigorously based on the Silnikov method, and the homoclinic orbit is found by using the undetermined coefficient method. Therefore, Smale horseshoe chaos occurs when electromagnetic stiffness changes. Numerical simulations are also given, which confirm the analytical results.
Frequency multiplying optoelectronic oscillator based on nonlinearly-coupled double loops.
Xu, Wei; Jin, Tao; Chi, Hao
2013-12-30
We propose and demonstrate a frequency multiplying optoelectronic oscillator with nonlinearly-coupled double loops based on two cascaded Mach-Zehnder modulators, to generate high frequency microwave signals using only low-frequency devices. We find the final oscillation modes are only determined by the length of the master oscillation loop. Frequency multiplying signals are generated via nonlinearly-coupled double loops, the output of one loop being used to modulate the other. In the experiments, microwave signals at 10 GHz with -121 dBc/Hz phase noise at 10 kHz offset and 20 GHz with -112.8 dBc/Hz phase noise at 10 kHz offset are generated. Meanwhile, their side-mode suppression ratios are also evaluated and the maximum ratio of 70 dB is obtained. PMID:24514845
Phase-shift-controlled logic gates in Y-shaped nonlinearly coupled chains.
Assunção, T F; Nascimento, E M; Sombra, A S B; Lyra, M L
2016-02-01
We introduce a model system composed of two input discrete chains nonlinearly coupled to a single output chain which mimics the geometry of Y-shaped carbon nanotubes, photonic crystal wave guides, and DNA junctions. We explore the capability of the proposed system to perform logic gate operations based on the transmission of phase-shifted harmonic incoming waves. Within a tight-binding approach, we determine the exact transmission spectrum which exhibits a nonlinear induced bistability. Using a digitalization scheme of the output signal based on amplitude modulation, we show that AND, OR, and XOR logic operations can be achieved. Nonlinearity strongly favors the realization of logic operations in the regime of large wavelengths, while phase shifting is required for the OR logic gate to be realizable. A detailed analysis of the contrast ratio shows that optimal operation of the AND and OR logic gates takes place when the nonlinear response is the predominant physical property distinguishing the coupling and regular sites. These results point towards the possibility of Y-branched junctions to perform logic operations based on the transmission of traveling waves. PMID:26986342
Nonlinear mode coupling and internal resonances in MoS{sub 2} nanoelectromechanical system
Samanta, C.; Yasasvi Gangavarapu, P. R.; Naik, A. K.
2015-10-26
Atomically thin two dimensional (2D) layered materials have emerged as a new class of material for nanoelectromechanical systems (NEMS) due to their extraordinary mechanical properties and ultralow mass density. Among them, graphene has been the material of choice for nanomechanical resonator. However, recent interest in 2D chalcogenide compounds has also spurred research in using materials such as MoS{sub 2} for the NEMS applications. As the dimensions of devices fabricated using these materials shrink down to atomically thin membrane, strain and nonlinear effects have become important. A clear understanding of the nonlinear effects and the ability to manipulate them is essential for next generation sensors. Here, we report on all electrical actuation and detection of few-layer MoS{sub 2} resonator. The ability to electrically detect multiple modes and actuate the modes deep into the nonlinear regime enables us to probe the nonlinear coupling between various vibrational modes. The modal coupling in our device is strong enough to detect three distinct internal resonances.
Quantum backaction and noise interference in asymmetric two-cavity optomechanical systems
NASA Astrophysics Data System (ADS)
Yanay, Yariv; Sankey, Jack C.; Clerk, Aashish A.
2016-06-01
We study the effect of cavity damping asymmetries on backaction in a "membrane-in-the-middle" optomechanical system, where a mechanical mode modulates the coupling between two photonic modes. We show that when the energy difference between the optical modes dominates (i.e., in the adiabatic limit) this system generically realizes a dissipative optomechanical coupling, with an effective position-dependent photonic damping rate. The resulting quantum noise interference can be used to ground-state cool a mechanical resonator in the unresolved sideband regime. We explicitly demonstrate how quantum noise interference controls linear backaction effects and show that this interference persists even outside the adiabatic limit. For a one-port cavity in the extreme bad cavity limit, the interference allows one to cancel all linear backaction effects. This allows continuous measurements of position-squared, with no stringent constraints on the single-photon optomechanical coupling strength. In contrast, such a complete cancellation is not possible in the good cavity limit. This places strict bounds on the optomechanical coupling required for quantum nondemolition measurements of mechanical energy, even in a one-port device.
NASA Technical Reports Server (NTRS)
Smith, David D.
2002-01-01
This talk will review the linear and nonlinear optical properties of metal nanoparticles and dielectric microparticles, with an emphasis on local field effects, and whispering gallery modes (WGMs), as well as the conjunction of these two effects for enhanced Raman. In particular, enhanced optical properties that result from electromagnetic coupling effects will be discussed in the context of Mie scattering from concentric spheres and bispheres. Predictions of mode splitting and photonic bandgaps in micro-spheres will be presented and will be shown to be analogous to effects that occur in coupled resonator optical waveguides (CROW). Slow and fast light in SCISSOR / CROW configurations will also be discussed.
Finite-size-induced transitions to synchrony in oscillator ensembles with nonlinear global coupling
NASA Astrophysics Data System (ADS)
Komarov, Maxim; Pikovsky, Arkady
2015-08-01
We report on finite-sized-induced transitions to synchrony in a population of phase oscillators coupled via a nonlinear mean field, which microscopically is equivalent to a hypernetwork organization of interactions. Using a self-consistent approach and direct numerical simulations, we argue that a transition to synchrony occurs only for finite-size ensembles and disappears in the thermodynamic limit. For all considered setups, which include purely deterministic oscillators with or without heterogeneity in natural oscillatory frequencies, and an ensemble of noise-driven identical oscillators, we establish scaling relations describing the order parameter as a function of the coupling constant and the system size.
Cluster Consensus of Nonlinearly Coupled Multi-Agent Systems in Directed Graphs
NASA Astrophysics Data System (ADS)
Lu, Xiao-Qing; Francis, Austin; Chen, Shi-Hua
2010-05-01
We investigate the cluster consensus problem in directed networks of nonlinearly coupled multi-agent systems by using pinning control. Depending on the community structure generated by the group partition of the underlying digraph, various clusters can be made coherently independent by applying feedback injections to a fraction of the agents. Sufficient conditions for cluster consensus are obtained using algebraic graph theory and matrix theory and some simulations results are included to illustrate the method.
Coupling a sensory hair-cell bundle to cyber clones enhances nonlinear amplification
Barral, Jérémie; Dierkes, Kai; Lindner, Benjamin; Jülicher, Frank; Martin, Pascal
2010-01-01
The vertebrate ear benefits from nonlinear mechanical amplification to operate over a vast range of sound intensities. The amplificatory process is thought to emerge from active force production by sensory hair cells. The mechano-sensory hair bundle that protrudes from the apical surface of each hair cell can oscillate spontaneously and function as a frequency-selective, nonlinear amplifier. Intrinsic fluctuations, however, jostle the response of a single hair bundle to weak stimuli and seriously limit amplification. Most hair bundles are mechanically coupled by overlying gelatinous structures. Here, we assayed the effects of mechanical coupling on the hair-bundle amplifier by combining dynamic force clamp of a hair bundle from the bullfrog’s saccule with real-time stochastic simulations of hair-bundle mechanics. This setup couples the hair bundle to two virtual hair bundles, called cyber clones, and mimics a situation in which the hair bundle is elastically linked to two neighbors with similar characteristics. We found that coupling increased the coherence of spontaneous hair-bundle oscillations. By effectively reducing noise, the synergic interplay between the hair bundle and its cyber clones also enhanced amplification of sinusoidal stimuli. All observed effects of coupling were in quantitative agreement with simulations. We argue that the auditory amplifier relies on hair-bundle cooperation to overcome intrinsic noise limitations and achieve high sensitivity and sharp frequency selectivity. PMID:20404191
Experimental characterization and modeling of non-linear coupling of the LHCD power on Tore Supra
Preynas, M.; Goniche, M.; Hillairet, J.; Litaudon, X.; Ekedahl, A.
2014-02-12
To achieve steady state operation on future tokamaks, in particular on ITER, the unique capability of a LHCD system to efficiently drive off-axis non-inductive current is needed. In this context, it is of prime importance to study and master the coupling of LH wave to the core plasma at high power density (tens of MW/m{sup 2}). In some specific conditions, deleterious effects on the LHCD coupling are sometimes observed on Tore Supra. At high power the waves may modify the edge parameters that change the wave coupling properties in a non-linear manner. In this way, dedicated LHCD experiments have been performed using the LHCD system of Tore Supra, composed of two different conceptual designs of launcher: the Fully Active Multijunction (FAM) and the new Passive Active Multijunction (PAM) antennas. A nonlinear interaction between the electron density and the electric field has been characterized in a thin plasma layer in front of the two LHCD antennas. The resulting dependence of the power reflection coefficient with the LHCD power, leading occasionally to trips in the output power, is not predicted by the standard linear theory of the LH wave coupling. Therefore, it is important to investigate and understand the possible origin of such non-linear effects in order to avoid their possible deleterious consequences. The PICCOLO-2D code, which self-consistently treats the wave propagation in the antenna vicinity and its interaction with the local edge plasma density, is used to simulate Tore Supra discharges. The simulation reproduces very well the occurrence of a non-linear behavior in the coupling observed in the LHCD experiments. The important differences and trends between the FAM and the PAM antennas, especially a larger increase in RC for the FAM, are also reproduced by the PICCOLO-2D simulation. The working hypothesis of the contribution of the ponderomotive effect in the non-linear observations of LHCD coupling is therefore validated through this comprehensive
NASA Astrophysics Data System (ADS)
Charalampidis, E. G.; Kevrekidis, P. G.; Frantzeskakis, D. J.; Malomed, B. A.
2016-08-01
We consider a two-component, two-dimensional nonlinear Schrödinger system with unequal dispersion coefficients and self-defocusing nonlinearities, chiefly with equal strengths of the self- and cross-interactions. In this setting, a natural waveform with a nonvanishing background in one component is a vortex, which induces an effective potential well in the second component, via the nonlinear coupling of the two components. We show that the potential well may support not only the fundamental bound state, but also multiring excited radial state complexes for suitable ranges of values of the dispersion coefficient of the second component. We systematically explore the existence, stability, and nonlinear dynamics of these states. The complexes involving the excited radial states are weakly unstable, with a growth rate depending on the dispersion of the second component. Their evolution leads to transformation of the multiring complexes into stable vortex-bright solitons ones with the fundamental state in the second component. The excited states may be stabilized by a harmonic-oscillator trapping potential, as well as by unequal strengths of the self- and cross-repulsive nonlinearities.
Transport of quantum excitations coupled to spatially extended nonlinear many-body systems
NASA Astrophysics Data System (ADS)
Iubini, Stefano; Boada, Octavi; Omar, Yasser; Piazza, Francesco
2015-11-01
The role of noise in the transport properties of quantum excitations is a topic of great importance in many fields, from organic semiconductors for technological applications to light-harvesting complexes in photosynthesis. In this paper we study a semi-classical model where a tight-binding Hamiltonian is fully coupled to an underlying spatially extended nonlinear chain of atoms. We show that the transport properties of a quantum excitation are subtly modulated by (i) the specific type (local versus non-local) of exciton-phonon coupling and by (ii) nonlinear effects of the underlying lattice. We report a non-monotonic dependence of the exciton diffusion coefficient on temperature, in agreement with earlier predictions, as a direct consequence of the lattice-induced fluctuations in the hopping rates due to long-wavelength vibrational modes. A standard measure of transport efficiency confirms that both nonlinearity in the underlying lattice and off-diagonal exciton-phonon coupling promote transport efficiency at high temperatures, preventing the Zeno-like quench observed in other models lacking an explicit noise-providing dynamical system.
Nitzan, Sarah H; Zega, Valentina; Li, Mo; Ahn, Chae H; Corigliano, Alberto; Kenny, Thomas W; Horsley, David A
2015-01-01
Parametric amplification, resulting from intentionally varying a parameter in a resonator at twice its resonant frequency, has been successfully employed to increase the sensitivity of many micro- and nano-scale sensors. Here, we introduce the concept of self-induced parametric amplification, which arises naturally from nonlinear elastic coupling between the degenerate vibration modes in a micromechanical disk-resonator, and is not externally applied. The device functions as a gyroscope wherein angular rotation is detected from Coriolis coupling of elastic vibration energy from a driven vibration mode into a second degenerate sensing mode. While nonlinear elasticity in silicon resonators is extremely weak, in this high quality-factor device, ppm-level nonlinear elastic effects result in an order-of-magnitude increase in the observed sensitivity to Coriolis force relative to linear theory. Perfect degeneracy of the primary and secondary vibration modes is achieved through electrostatic frequency tuning, which also enables the phase and frequency of the parametric coupling to be varied, and we show that the resulting phase and frequency dependence of the amplification follow the theory of parametric resonance. We expect that this phenomenon will be useful for both fundamental studies of dynamic systems with low dissipation and for increasing signal-to-noise ratio in practical applications such as gyroscopes. PMID:25762243
NASA Astrophysics Data System (ADS)
Nitzan, Sarah H.; Zega, Valentina; Li, Mo; Ahn, Chae H.; Corigliano, Alberto; Kenny, Thomas W.; Horsley, David A.
2015-03-01
Parametric amplification, resulting from intentionally varying a parameter in a resonator at twice its resonant frequency, has been successfully employed to increase the sensitivity of many micro- and nano-scale sensors. Here, we introduce the concept of self-induced parametric amplification, which arises naturally from nonlinear elastic coupling between the degenerate vibration modes in a micromechanical disk-resonator, and is not externally applied. The device functions as a gyroscope wherein angular rotation is detected from Coriolis coupling of elastic vibration energy from a driven vibration mode into a second degenerate sensing mode. While nonlinear elasticity in silicon resonators is extremely weak, in this high quality-factor device, ppm-level nonlinear elastic effects result in an order-of-magnitude increase in the observed sensitivity to Coriolis force relative to linear theory. Perfect degeneracy of the primary and secondary vibration modes is achieved through electrostatic frequency tuning, which also enables the phase and frequency of the parametric coupling to be varied, and we show that the resulting phase and frequency dependence of the amplification follow the theory of parametric resonance. We expect that this phenomenon will be useful for both fundamental studies of dynamic systems with low dissipation and for increasing signal-to-noise ratio in practical applications such as gyroscopes.
Optomechanics: Listening to quantum grains of sound
NASA Astrophysics Data System (ADS)
Favero, Ivan
2015-04-01
An optomechanical device has allowed quanta, or 'grains', of mechanical vibration to be counted by optical means. The system may open up new possibilities in acoustics and thermal engineering. See Letter p.522
Nonlinear mode coupling in optical fibers and VCSELs and some applications to communication systems
NASA Astrophysics Data System (ADS)
Kishore, Kunal
2000-11-01
Nonlinear phenomena are relatively easy to observe in optical fibers and semiconductor laser cavities. In optical fibers, nonlinear effects can be seen even at low power due to the high intensities in the small fiber cores and long propagation distances possible in low loss fibers. Semiconductor lasers, in particular, vertical cavity surface emitting lasers (VCSELs), have cavities with very high Q-factors, which result in high intra cavity intensities even at low facet powers. In this thesis we will examine how these nonlinear effects are responsible for coupling between the different modes present in the medium and some applications to optical communication systems. In optical fibers, the nonlinear processes that dominate are self-phase matched processes that automatically satisfy the phase matching condition. These processes include self phase modulation (SPM) and cross phase modulation (XPM). SPM is responsible for the stability and interaction between propagating pulses known as solitons. XPM is responsible for coupling signals with different polarizations or wavelengths propagating in a fiber. In this thesis we have investigated the possibility of controlling the non-linear interaction between solitons, using XPM from another pulse and using this mechanism for pattern recognition in an optical data stream. We demonstrate high-speed (63Gb/s) recognition of 8-bit header words which is a useful function at an add- drop node in an optical network. Both SPM and XPM can be explained in terms of a nonlinear refractive index-a simplification that is made possible by the extremely fast relaxation times in silica (~40fs). In semiconductors the carriers exhibit both fast intra band (~50fs) and spin-flip relaxation (~2ps), and slow inter band dipole relaxation (~Ins). Due to this hierarchy of relaxation times, the interaction of light with the semiconductor medium cannot be described by a single effective refractive index and the carrier dynamics have to be accounted for
Dynamical localization of matter waves in optomechanics
NASA Astrophysics Data System (ADS)
Ayub, Muhammad; Ammar Yasir, Kashif; Saif, Farhan
2014-11-01
We explain dynamical localization of Bose-Einstein condensate (BEC) in optomechanics both in position and in momentum space. The experimentally realizable optomechanical system is a Fabry-Pérot cavity with one moving end mirror driven by a single mode standing field. In our study we analyze variations in modulation strength and effective Planck’s constant. Keeping in mind present day experimental advancements, we suggest parameteric values to observe the phenomenon in the laboratory.
Design and Construction of Cryogenic Optomechanical System
NASA Astrophysics Data System (ADS)
Lee, Donghun; Underwood, Mitchell; Mason, David; Jayich, Andrew; Kashkanova, Anya; Harris, Jack
2013-03-01
One key challenge to observing quantum phenomena in a macroscopic mechanical oscillator is reaching its ground state. To achieve the low temperatures required for this, we utilize resolved sideband laser cooling of a few hundred kHz mechanical oscillator with high mechanical Q (a Si3N4 membrane) inside a high finesse optical cavity, in addition to cryogenically reducing the bath temperature. Realizing high Q and high finesse cavity optomechanical devices in a cryogenic environment requires overcoming a number of challenges. In this talk, we describe the design and construction of such a device working at a bath temperature of 300 mK (in a 3He refrigerator) and suited for operation at lower temperatures (in a dilution refrigerator). The design incorporates in-situ commercial piezo actuators (manufactured by Janssen Precision Engineering) to couple externally prepared laser light into the cold optical cavity. The design also incorporates filtering cavities to suppress classical laser noise, and acoustic and seismic isolation of the experiment.
Nested trampoline resonators for optomechanics
NASA Astrophysics Data System (ADS)
Weaver, M. J.; Pepper, B.; Luna, F.; Buters, F. M.; Eerkens, H. J.; Welker, G.; Perock, B.; Heeck, K.; de Man, S.; Bouwmeester, D.
2016-01-01
Two major challenges in the development of optomechanical devices are achieving a low mechanical and optical loss rate and vibration isolation from the environment. We address both issues by fabricating trampoline resonators made from low pressure chemical vapor deposition Si3N4 with a distributed Bragg reflector mirror. We design a nested double resonator structure with 80 dB of mechanical isolation from the mounting surface at the inner resonator frequency, and we demonstrate up to 45 dB of isolation at lower frequencies in agreement with the design. We reliably fabricate devices with mechanical quality factors of around 400 000 at room temperature. In addition, these devices were used to form optical cavities with finesse up to 181 000 ± 1000. These promising parameters will enable experiments in the quantum regime with macroscopic mechanical resonators.
Triple optomechanical induced transparency in a two-cavity system
NASA Astrophysics Data System (ADS)
Shi-Chao, Wu; Li-Guo, Qin; Jun, Jing; Guo-Hong, Yang; Zhong-Yang, Wang
2016-05-01
We theoretically investigate the optomechanical induced transparency (OMIT) phenomenon in a two-cavity system which is composed of two optomechanical cavities. Both of the cavities consist of a fixed mirror and a high-Q mechanical resonator, and they couple to each other via a common waveguide. We show that in the presence of a strong pump field applied to one cavity and a weak probe field applied to the other, a triple-OMIT can be observed in the output field at the probe frequency. The two mechanical resonators in the two cavities are identical, but they lead to different quantum interference pathways. The transparency windows are induced by the coupling of the two cavities and the optical pressure radiated to the mechanical resonators, which can be controlled via the power of the pump field and the coupling strength of the two cavities. Project supported by the Strategic Priority Research Program, China (Grant No. XDB01010200), the Hundred Talents Program of the Chinese Academy of Sciences (Grant No. Y321311401), and the National Natural Sciences Foundation of China (Grant Nos. 11347147 and 1547035).
Laser cooling of a harmonic oscillator's bath with optomechanics
NASA Astrophysics Data System (ADS)
Xu, Xunnong; Taylor, Jacob
Thermal noise reduction in mechanical systems is a topic both of fundamental interest for studying quantum physics at the macroscopic level and for application of interest, such as building high sensitivity mechanics based sensors. Similar to laser cooling of neutral atoms and trapped ions, the cooling of mechanical motion by radiation pressure can take single mechanical modes to their ground state. Conventional optomechanical cooling is able to introduce additional damping channel to mechanical motion, while keeping its thermal noise at the same level, and as a consequence, the effective temperature of the mechanical mode is lowered. However, the ratio of temperature to quality factor remains roughly constant, preventing dramatic advances in quantum sensing using this approach. Here we propose an efficient scheme for reducing the thermal load on a mechanical resonator while improving its quality factor. The mechanical mode of interest is assumed to be weakly coupled to its heat bath but strongly coupled to a second mechanical mode, which is cooled by radiation pressure coupling to a red detuned cavity field. We also identify a realistic optomechanical design that has the potential to realize this novel cooling scheme. Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742, USA.
Nonlinear dynamics approach to the predictability of the Cane-Zebiak coupled ocean-atmosphere model
NASA Astrophysics Data System (ADS)
Siqueira, L.; Kirtman, B.
2014-01-01
The predictability of the Cane-Zebiak coupled ocean-atmosphere model is investigated using nonlinear dynamics analysis. Newer theoretical concepts are applied to the coupled model in order to help quantify maximal prediction horizons for finite amplitude perturbations on different scales. Predictability analysis based on the maximum Lyapunov exponent considers infinitesimal perturbations, which are associated with errors in the smallest fastest-evolving scales of motion. However, these errors become irrelevant for the predictability of larger scale motions. In this study we employed finite-size Lyapunov exponent analysis to assess the predictability of the Cane-Zebiak coupled ocean-atmosphere model as a function of scale. We demonstrate the existence of fast and slow timescales, as noted in earlier studies, and the expected enhanced predictability of the anomalies on large scales. The final results and conclusions clarify the applicability of these new methods to seasonal forecasting problems.
NASA Astrophysics Data System (ADS)
Li, Long-Xing; Liu, Jun; Dai, Zheng-De; Liu, Ren-Lang
2014-09-01
In this work, the rational homoclinic solution (rogue wave solution) can be obtained via the classical homoclinic solution for the nonlinear Schrödinger (NLS) equation and the coupled nonlinear Schrödinger (CNLS) equation, respectively. This is a new way for generating rogue wave comparing with direct constructing method and Darboux dressing technique
NASA Astrophysics Data System (ADS)
Yasumoto, K.; Mitsunaga, N.; Maeda, H.
1996-03-01
A planar three-waveguide nonlinear directional coupler (NLDC) is analyzed by the use of a coupled-mode approach based on the singular perturbation technique. The self-consistent first-order coupled-mode equations are derived in an analytically closed form, which demonstrates that the power transfer in three-waveguide NLDC is described by linear-coupling terms and nonlinear self-modulation terms. The optical switching characteristics predicted by the coupled-mode theory are discussed and shown to be in good agreement with those obtained from a numerical analysis with the finite-difference beam-propagation method.
Linear and nonlinear heavy ion-acoustic waves in a strongly coupled plasma
Ema, S. A. Mamun, A. A.; Hossen, M. R.
2015-09-15
A theoretical study on the propagation of linear and nonlinear heavy ion-acoustic (HIA) waves in an unmagnetized, collisionless, strongly coupled plasma system has been carried out. The plasma system is assumed to contain adiabatic positively charged inertial heavy ion fluids, nonextensive distributed electrons, and Maxwellian light ions. The normal mode analysis is used to study the linear behaviour. On the other hand, the well-known reductive perturbation technique is used to derive the nonlinear dynamical equations, namely, Burgers equation and Korteweg-de Vries (K-dV) equation. They are also numerically analyzed in order to investigate the basic features of shock and solitary waves. The adiabatic effects on the HIA shock and solitary waves propagating in such a strongly coupled plasma are taken into account. It has been observed that the roles of the adiabatic positively charged heavy ions, nonextensivity of electrons, and other plasma parameters arised in this investigation have significantly modified the basic features (viz., polarity, amplitude, width, etc.) of the HIA solitary/shock waves. The findings of our results obtained from this theoretical investigation may be useful in understanding the linear as well as nonlinear phenomena associated with the HIA waves both in space and laboratory plasmas.
Modeling and analysis of electric and magnetic coupled problems under nonlinear conditions
NASA Astrophysics Data System (ADS)
Geri, A.; La Rosa, M.; Veca, G. M.
1994-05-01
In this paper the authors define a numerical method to solve nonlinear combined magnetic and electric problems using reliable general purpose calculation codes. This method has been applied to analyze the behavior of a busbar system built with a saturable steel enclosure and connected with an arbitrary external circuit. The enclosure magnetic characteristics have been determined by means of experimental tests executed by the authors. To analyze this electrical system, the skin and proximity effects in the massive conductors, as well as the load conditions of the external circuit, must be taken into account. The present formulation permits us to solve the previously described coupled problems by means of an iterative procedure. Using this technique, it is possible to solve separately the field and the circuit equations by means of specific codes. In particular, an iterative procedure it is pointed out so defined: for each estimated load condition, a finite element code has been used to evaluate the relating busbar cross parameters, taking into account the nonlinear behavior of the steel enclosure, while, for each assigned set of the busbar cross parameters, a circuit simulator has been used to determine the relating load conditions of the busbar. In addition, a specialized post-processor has been developed to manage the data flow between the calculation codes. The originality of this work is linked to the use of general purpose commercial software to solve the nonlinear magnetic and electric coupled problems.
Combination of sLORETA and Nonlinear Coupling for Emotional EEG Source Localization.
Goshvarpour, Ateke; Abbasi, Ataollah; Goshvarpour, Atefeh
2016-07-01
The objective of the present study is to investigate the anatomical distribution of the cortical sources of emotional response to music videos by means of electroencephalogram (EEG) analysis. A novel methodology is introduced to determine the nonlinear couplings between different brain regions based on the coherence analysis, nonlinear features of EEG recordings and a source localization method, standard low resolution electromagnetic tomography (sLORETA). 32 channels of EEG time series of 32 subjects available in DEAP database were studied. The Lyapunov exponents and approximate entropy were applied to the EEG. The coherence for Lyapunov exponents and approximate entropy were calculated between each electrode paired to all other electrodes. Considering valence and arousal related effects, the sLORETA was applied to each above mentioned feature to determine emotional processing cortices. Using the proposed methodology, significant differences in sLORETA activity are observed between different emotional states. These changes were dominantly localized in the Brodmann 11 area (frontal lobe). In addition, some evidences provided that the left hemisphere is more activated to valence and arousal-related effects. Results suggest that considering two dimensions of emotions concurrently, a wider brain region was dominated in synchronization: superior frontal gyrus, middle frontal gyrus, and superior parietal lobule. Cooperating nonlinear coupling along with EEG source localization methods could provide an interesting tool for understanding the cortical specialization in emotional processes. PMID:27262422
Linear and nonlinear heavy ion-acoustic waves in a strongly coupled plasma
NASA Astrophysics Data System (ADS)
Ema, S. A.; Hossen, M. R.; Mamun, A. A.
2015-09-01
A theoretical study on the propagation of linear and nonlinear heavy ion-acoustic (HIA) waves in an unmagnetized, collisionless, strongly coupled plasma system has been carried out. The plasma system is assumed to contain adiabatic positively charged inertial heavy ion fluids, nonextensive distributed electrons, and Maxwellian light ions. The normal mode analysis is used to study the linear behaviour. On the other hand, the well-known reductive perturbation technique is used to derive the nonlinear dynamical equations, namely, Burgers equation and Korteweg-de Vries (K-dV) equation. They are also numerically analyzed in order to investigate the basic features of shock and solitary waves. The adiabatic effects on the HIA shock and solitary waves propagating in such a strongly coupled plasma are taken into account. It has been observed that the roles of the adiabatic positively charged heavy ions, nonextensivity of electrons, and other plasma parameters arised in this investigation have significantly modified the basic features (viz., polarity, amplitude, width, etc.) of the HIA solitary/shock waves. The findings of our results obtained from this theoretical investigation may be useful in understanding the linear as well as nonlinear phenomena associated with the HIA waves both in space and laboratory plasmas.
Nonlinear coupling of low-n modes in PBX-M
Sesnic, S.; Kaita, R.; Kaye, S.; Okabayashi, M.; Bell, R.E.; Kugel, H.W.; Leblanc, B.; Takahashi, H.; Gammel, G.M. |; Holland, A. |; Levinton, F.M. |; Powers, E.J.; Im, S.
1994-03-01
In many of the medium and high beta discharges in PBX-M low-n modes with different n-numbers are observed. The probability of a low-n mode to be excited decreases with increasing n-number. If two modes of different frequency and n-number ({omega}{sub 1} and {omega}{sub 2}; k{sub 1} and k{sub 2}) are simultaneously present in the plasma, these modes interact nonlinearly and create sidebands in frequency ({omega}{sub 2}{+-}{omega}{sub 1}) and wave-number (k{sub 2}{+-}k{sub 1} or n{sub 2}{+-}n{sub 1} and m{sub 2}{+-}m{sub 1}). If these fundamental modes, {omega}{sub 1}/k{sub 1} and {omega}{sub 2}/k{sub 2}, contain strong harmonics, the harmonics also interact nonlinearly, creating more nonlinear products: k{omega}{sub 2}{+-}l{omega}{sub 1} and kk{sub 2}{+-}lk{sub 1}, where k and l are integers describing the harmonics. These modes, the products of nonlinear interaction between two fundamental modes, most probably have a kink character. During this three-wave coupling interaction, a decrease in neutron rate and an enhanced loss of medium energy ions are observed.
Nonlinear microwave photon occupancy of a driven resonator strongly coupled to a transmon qubit
NASA Astrophysics Data System (ADS)
Suri, B.; Keane, Z. K.; Bishop, Lev S.; Novikov, S.; Wellstood, F. C.; Palmer, B. S.
2015-12-01
We measure photon occupancy in a thin-film superconducting lumped element resonator coupled to a transmon qubit at 20 mK and find a nonlinear dependence on the applied microwave power. The transmon-resonator system was operated in the strong dispersive regime, where the ac Stark shift (2 χ ) due to a single microwave photon present in the resonator was larger than the linewidth (Γ ) of the qubit transition. When the resonator was coherently driven at 5.474 325 GHz, the transition spectrum of the transmon at 4.982 GHz revealed well-resolved peaks, each corresponding to an individual photon number-state of the resonator. From the relative peak heights we obtain the occupancy of the photon states and the average photon occupancy n ¯ of the resonator. We observe a nonlinear variation of n ¯ with the applied drive power Prf for n ¯<5 and compare our results to numerical simulations of the system-bath master equation in the steady state, as well as to a semiclassical model for the resonator that includes the Jaynes-Cummings interaction between the transmon and the resonator. We find good quantitative agreement using both models and analysis reveals that the nonlinear behavior is principally due to shifts in the resonant frequency caused by a qubit-induced Jaynes-Cummings nonlinearity.
NASA Astrophysics Data System (ADS)
Armero, F.; Simo, J. C.
This article describes new a priori stability estimates for the full nonlinear system of coupled thermoplasticity at finite strains and presents a fractional step method leading to a new class of unconditionally stable staggered algorithms. These results are shown to hold for general models of multiplicative plasticity that include, as a particular case, the single-crystal model. The proposed product formula algorithm is designed via an entropy based operator split that yields one of the first known staggered algorithms that retains the property of nonlinear unconditional stability. The scheme employs an isentropic step, in which the total entropy is held constant, followed by a heat conduction step (with nonlinear source) at fixed configuration. The nonlinear stability analysis shows that the proposed staggered scheme inherits the a priori energy estimate for the continuum problem, regardless of the size of the time-step. In sharp contrast with these results, it is shown that widely used staggered methods employing an isothermal step followed by a heat conduction problem can be at most only conditionally stable. The excellent performance of the methodology is illustrated in representative numerical simulations.
The nonlinear bifurcation and chaos of coupled heave and pitch motions of a truss spar platform
NASA Astrophysics Data System (ADS)
Huang, Lei; Liu, Liqin; Liu, Chunyuan; Tang, Yougang
2015-10-01
This paper presents the results from a numerical study on the nonlinear dynamic behaviors including bifurcation and chaos of a truss spar platform. In view of the mutual influences between the heave and the pitch modes, the coupled heave and pitch motion equations of the spar platform hull were established in the regular waves. In order to analyze the nonlinear motions of the platform, three-dimensional maximum Lyapunov exponent graphs and the bifurcation graphs were constructed, the Poincaré maps and the power spectrums of the platform response were calculated. It was found that the platform motions are sensitive to wave frequency. With changing wave frequency, the platform undergoes complicated nonlinear motions, including 1/2 sub-harmonic motion, quasi-periodic motion and chaotic motion. When the wave frequency approaches the natural frequency of the heave mode of the platform, the platform moves with quasi-periodic motion and chaotic motional ternately. For a certain range of wave frequencies, the platform moves with totally chaotic motion. The range of wave frequencies which leads to chaotic motion of the platform increases with increasing wave height. The three-dimensional maximum Lyapunov exponent graphs and the bifurcation graphs reveal the nonlinear motions of the spar platform under different wave conditions.
Garcés, Rafael; de Valcárcel, Germán J.
2016-01-01
Squeezed light, displaying less fluctuation than vacuum in some observable, is key in the flourishing field of quantum technologies. Optical or microwave cavities containing a Kerr nonlinearity are known to potentially yield large levels of squeezing, which have been recently observed in optomechanics and nonlinear superconducting circuit platforms. Such Kerr-cavity squeezing however suffers from two fundamental drawbacks. First, optimal squeezing requires working close to turning points of a bistable cycle, which are highly unstable against noise thus rendering optimal squeezing inaccessible. Second, the light field has a macroscopic coherent component corresponding to the pump, making it less versatile than the so-called squeezed vacuum, characterised by a null mean field. Here we prove analytically and numerically that the bichromatic pumping of optomechanical and superconducting circuit cavities removes both limitations. This finding should boost the development of a new generation of robust vacuum squeezers in the microwave and optical domains with current technology. PMID:26916946
NASA Technical Reports Server (NTRS)
Thienel, Julie; Sanner, Robert M.
2002-01-01
A nonlinear control scheme for attitude control of a spacecraft is combined with a nonlinear gyro misalignment and bias observer for the case of constant gyro misalignment and bias. A persistency of excitation analysis shows the observer gyro bias estimates converge to the true bias values exponentially fast. The convergence of the misalignment estimates is also presented. Then; the resulting coupled, closed loop dynamics are proven by a Lyapunov analysis to be globally stable, with asymptotically perfect tracking. The analysis is extended to consider the effects of noise in addition to the gyro misalignment and bias. A simulation of the proposed observer-controller design is given for a rigid spacecraft tracking a specified, time-varying attitude sequence to illustrate the theoretical claims.
Assessing Aircraft Susceptibility to Nonlinear Aircraft-Pilot Coupling/Pilot-Induced Oscillations
NASA Technical Reports Server (NTRS)
Hess, R.A.; Stout, P. W.
1997-01-01
A unified approach for assessing aircraft susceptibility to aircraft-pilot coupling (or pilot-induced oscillations) which was previously reported in the literature and applied to linear systems is extended to nonlinear systems, with emphasis upon vehicles with actuator rate saturation. The linear methodology provided a tool for predicting: (1) handling qualities levels, (2) pilot-induced oscillation rating levels and (3) a frequency range in which pilot-induced oscillations are likely to occur. The extension to nonlinear systems provides a methodology for predicting the latter two quantities. Eight examples are presented to illustrate the use of the technique. The dearth of experimental flight-test data involving systematic variation and assessment of the effects of actuator rate limits presently prevents a more thorough evaluation of the methodology.
NASA Astrophysics Data System (ADS)
Sharma, Dinkar; Singh, Prince; Chauhan, Shubha
2016-01-01
In this paper, a combined form of the Laplace transform method with the homotopy perturbation method (HPTM) is applied to solve nonlinear systems of partial differential equations viz. the system of third order KdV Equations and the systems of coupled Burgers' equations in one- and two- dimensions. The nonlinear terms can be easily handled by the use of He's polynomials. The results shows that the HPTM is very efficient, simple and avoids the round-off errors. Four test examples are considered to illustrate the present scheme. Further the results are compared with Homotopy perturbation method (HPM) which shows that this method is a suitable method for solving systems of partial differential equations.
Mushtaq, A.; Saeed, R.; Haque, Q.
2011-04-15
Linear and nonlinear coupled electrostatic drift and ion acoustic waves are studied in inhomogeneous, collisional pair ion-electron plasma. The Korteweg-de Vries-Burgers (KdVB) equation for a medium where both dispersion and dissipation are present is derived. An attempt is made to obtain exact solution of KdVB equation by using modified tanh-coth method for arbitrary velocity of nonlinear drift wave. Another exact solution for KdVB is obtained, which gives a structure of shock wave. Korteweg-de Vries (KdV) and Burgers equations are derived in limiting cases with solitary and monotonic shock solutions, respectively. Effects of species density, magnetic field, obliqueness, and the acoustic to drift velocity ratio on the solitary and shock solutions are investigated. The results discussed are useful in understanding of low frequency electrostatic waves at laboratory pair ion plasmas.
A Haar wavelet collocation method for coupled nonlinear Schrödinger-KdV equations
NASA Astrophysics Data System (ADS)
Oruç, Ömer; Esen, Alaattin; Bulut, Fatih
2016-04-01
In this paper, to obtain accurate numerical solutions of coupled nonlinear Schrödinger-Korteweg-de Vries (KdV) equations a Haar wavelet collocation method is proposed. An explicit time stepping scheme is used for discretization of time derivatives and nonlinear terms that appeared in the equations are linearized by a linearization technique and space derivatives are discretized by Haar wavelets. In order to test the accuracy and reliability of the proposed method L2, L∞ error norms and conserved quantities are used. Also obtained results are compared with previous ones obtained by finite element method, Crank-Nicolson method and radial basis function meshless methods. Error analysis of Haar wavelets is also given.
Sun Zhiyuan; Yu Xin; Liu Ying; Gao Yitian
2012-12-15
We investigate the dynamics of the bound vector solitons (BVSs) for the coupled nonlinear Schroedinger equations with the nonhomogenously stochastic perturbations added on their dispersion terms. Soliton switching (besides soliton breakup) can be observed between the two components of the BVSs. Rate of the maximum switched energy (absolute values) within the fixed propagation distance (about 10 periods of the BVSs) enhances in the sense of statistics when the amplitudes of stochastic perturbations increase. Additionally, it is revealed that the BVSs with enhanced coherence are more robust against the perturbations with nonhomogenous stochasticity. Diagram describing the approximate borders of the splitting and non-splitting areas is also given. Our results might be helpful in dynamics of the BVSs with stochastic noises in nonlinear optical fibers or with stochastic quantum fluctuations in Bose-Einstein condensates.
A nonlinear magneto-thermo-elastic coupled hysteretic constitutive model for magnetostrictive alloys
NASA Astrophysics Data System (ADS)
Jin, Ke; Kou, Yong; Zheng, Xiaojing
2012-06-01
This paper presents a general hysteretic constitutive law of nonlinear magneto-thermo-elastic coupling for magnetostrictive alloys. The model considered here is thermodynamically motivated and based on the Gibbs free energy function. A nonlinear part of the elastic strain arising from magnetic domain rotation induced by the pre-stress is taken into account. Furthermore, the movement of the domain walls is incorporated to describe hysteresis based on Jiles-Atherton's model. Then a set of closed and analytical expressions of the constitutive law for the magnetostrictive rods and films are obtained, and the parameters appearing in the model can be determined by those measurable experiments in mechanics and physics. Comparing this model with other existing models in this field, the quantitative results show that the relationships obtained here are more effective to describe the effects of the pre-stress or in-plane residual stress and ambient temperature on the magnetization or the magnetostriction hysteresis loops.
Manipulation of light in a generalized coupled Nonlinear Schrödinger equation
NASA Astrophysics Data System (ADS)
Radha, R.; Vinayagam, P. S.; Porsezian, K.
2016-08-01
We investigate a generalized coupled nonlinear Schrodinger (GCNLS) equation containing Self-Phase Modulation (SPM), Cross-Phase Modulation (XPM) and Four Wave Mixing (FWM) describing the propagation of electromagnetic radiation through an optical fibre and generate the associated Lax-pair. We then construct bright solitons employing gauge transformation approach. The collisional dynamics of bright solitons indicates that it is not only possible to manipulate intensity (energy) between the two modes (optical beams), but also within a given mode unlike the Manakov model which does not have the same freedom. The freedom to manipulate intensity (energy) in a given mode or between two modes arises due to a suitable combination of SPM, XPM and FWM. While SPM and XPM are controlled by an arbitrary real parameter each, FWM is governed by two arbitrary complex parameters. The above model may have wider ramifications in nonlinear optics and Bose-Einstein Condensates (BECs).
Kudo, Kiwamu Suto, Hirofumi; Nagasawa, Tazumi; Mizushima, Koichi; Sato, Rie
2014-10-28
The fundamental function of any oscillator is to produce a waveform with a stable frequency. Here, we show a method of frequency stabilization for spin-torque nano-oscillators (STNOs) that relies on coupling with an adjacent nanomagnet through the magnetic dipole–dipole interaction. It is numerically demonstrated that highly stable oscillations occur as a result of mutual feedback between an STNO and a nanomagnet. The nanomagnet acts as a nonlinear resonator for the STNO. This method is based on the nonlinear behavior of the resonator and can be considered as a magnetic analogue of an optimization scheme in nanoelectromechanical systems. The oscillation frequency is most stabilized when the nanomagnet is driven at a special feedback point at which the feedback noise between the STNO and resonator is completely eliminated.
Scalable Nonlinear Solvers for Fully Implicit Coupled Nuclear Fuel Modeling. Final Report
Cai, Xiao-Chuan; Keyes, David; Yang, Chao; Zheng, Xiang; Pernice, Michael
2014-09-29
The focus of the project is on the development and customization of some highly scalable domain decomposition based preconditioning techniques for the numerical solution of nonlinear, coupled systems of partial differential equations (PDEs) arising from nuclear fuel simulations. These high-order PDEs represent multiple interacting physical fields (for example, heat conduction, oxygen transport, solid deformation), each is modeled by a certain type of Cahn-Hilliard and/or Allen-Cahn equations. Most existing approaches involve a careful splitting of the fields and the use of field-by-field iterations to obtain a solution of the coupled problem. Such approaches have many advantages such as ease of implementation since only single field solvers are needed, but also exhibit disadvantages. For example, certain nonlinear interactions between the fields may not be fully captured, and for unsteady problems, stable time integration schemes are difficult to design. In addition, when implemented on large scale parallel computers, the sequential nature of the field-by-field iterations substantially reduces the parallel efficiency. To overcome the disadvantages, fully coupled approaches have been investigated in order to obtain full physics simulations.
Stochastic dynamics and phase-field roughening in optomechanical oscillator arrays
NASA Astrophysics Data System (ADS)
Lauter, Roland; Mitra, Aditi; Marquardt, Florian
We consider arrays of coupled optomechanical systems, each of which consists of a laser-driven optical mode interacting with a mechanical (vibrational) mode. For sufficiently strong laser driving, the mechanical modes can settle into stable finite-amplitude oscillations on a limit cycle. We study the collective classical nonlinear dynamics of the phases of these oscillators, which is effectively described by an extension of the well-known Kuramoto model. In this extended model, we study the effect of noise on the dynamics in the case of homogeneous-phase initial conditions. We analytically establish a connection to the physics of surface growth as described by the Kardar-Parisi-Zhang model. Simulations of one-dimensional arrays of our model indeed show roughening of the phase field and universal scaling of the phase-field width. In contrast to the continuum Kardar-Parisi-Zhang model, our model is a genuine lattice model. We discuss interesting effects due to this difference, including crossover timescales and the role of instabilities of the roughening process.
Inversion of geothermal heat flux in a thermomechanically coupled nonlinear Stokes ice sheet model
NASA Astrophysics Data System (ADS)
Zhu, Hongyu; Petra, Noemi; Stadler, Georg; Isaac, Tobin; Hughes, Thomas J. R.; Ghattas, Omar
2016-07-01
We address the inverse problem of inferring the basal geothermal heat flux from surface velocity observations using a steady-state thermomechanically coupled nonlinear Stokes ice flow model. This is a challenging inverse problem since the map from basal heat flux to surface velocity observables is indirect: the heat flux is a boundary condition for the thermal advection-diffusion equation, which couples to the nonlinear Stokes ice flow equations; together they determine the surface ice flow velocity. This multiphysics inverse problem is formulated as a nonlinear least-squares optimization problem with a cost functional that includes the data misfit between surface velocity observations and model predictions. A Tikhonov regularization term is added to render the problem well posed. We derive adjoint-based gradient and Hessian expressions for the resulting partial differential equation (PDE)-constrained optimization problem and propose an inexact Newton method for its solution. As a consequence of the Petrov-Galerkin discretization of the energy equation, we show that discretization and differentiation do not commute; that is, the order in which we discretize the cost functional and differentiate it affects the correctness of the gradient. Using two- and three-dimensional model problems, we study the prospects for and limitations of the inference of the geothermal heat flux field from surface velocity observations. The results show that the reconstruction improves as the noise level in the observations decreases and that short-wavelength variations in the geothermal heat flux are difficult to recover. We analyze the ill-posedness of the inverse problem as a function of the number of observations by examining the spectrum of the Hessian of the cost functional. Motivated by the popularity of operator-split or staggered solvers for forward multiphysics problems - i.e., those that drop two-way coupling terms to yield a one-way coupled forward Jacobian - we study the
Rao, N.N.
1998-01-01
A systematic analysis of the stationary propagation of nonlinearly coupled electromagnetic and ion-acoustic waves in an unmagnetized plasma via the ponderomotive force is carried out. For small but finite amplitudes, the governing equations have a Hamiltonian structure, but with a kinetic energy term that is not positive definite. The Hamiltonian is similar to the well-known H{acute e}non{endash}Heiles Hamiltonian of nonlinear dynamics, and is completely integrable in three regimes of the allowed parameter space. The corresponding second invariants of motion are also explicitly obtained. The integrable parameter regimes correspond to supersonic values of the Mach number, which characterizes the propagation speed of the coupled waves. On the other hand, in the sub- as well as near-sonic regimes, the coupled mode equations admit different types of exact analytical solutions, which represent nonlinear localized eigenstates of the electromagnetic field trapped in the density cavity due to the ponderomotive potential. While the density cavity has always a single-dip structure, for larger amplitudes it can support higher-order modes having a larger number of nodes in the electromagnetic field. In particular, we show the existence of a new type of localized electromagnetic wave whose field intensity has a triple-hump structure. For typical parameter values, the triple-hump solitons propagate with larger Mach numbers that are closer to the sonic limit than the single- as well as the double-hump solitons, but carry a lesser amount of the electromagnetic field energy. A comparison between the different types of solutions is carried out. The possibility of the existence of trapped electromagnetic modes having a larger number of humps is also discussed. {copyright} {ital 1998 American Institute of Physics.}
Schüler, D.; Alonso, S.; Bär, M.; Torcini, A.
2014-12-15
Pattern formation often occurs in spatially extended physical, biological, and chemical systems due to an instability of the homogeneous steady state. The type of the instability usually prescribes the resulting spatio-temporal patterns and their characteristic length scales. However, patterns resulting from the simultaneous occurrence of instabilities cannot be expected to be simple superposition of the patterns associated with the considered instabilities. To address this issue, we design two simple models composed by two asymmetrically coupled equations of non-conserved (Swift-Hohenberg equations) or conserved (Cahn-Hilliard equations) order parameters with different characteristic wave lengths. The patterns arising in these systems range from coexisting static patterns of different wavelengths to traveling waves. A linear stability analysis allows to derive a two parameter phase diagram for the studied models, in particular, revealing for the Swift-Hohenberg equations, a co-dimension two bifurcation point of Turing and wave instability and a region of coexistence of stationary and traveling patterns. The nonlinear dynamics of the coupled evolution equations is investigated by performing accurate numerical simulations. These reveal more complex patterns, ranging from traveling waves with embedded Turing patterns domains to spatio-temporal chaos, and a wide hysteretic region, where waves or Turing patterns coexist. For the coupled Cahn-Hilliard equations the presence of a weak coupling is sufficient to arrest the coarsening process and to lead to the emergence of purely periodic patterns. The final states are characterized by domains with a characteristic length, which diverges logarithmically with the coupling amplitude.
Non-linear curvature perturbation in multi-field inflation models with non-minimal coupling
White, Jonathan; Minamitsuji, Masato; Sasaki, Misao E-mail: masato.minamitsuji@ist.utl.pt
2013-09-01
Using the δN formalism we consider the non-linear curvature perturbation in multi-field models of inflation with non-minimal coupling. In particular, we focus on the relation between the δN formalism as applied in the conformally related Jordan and Einstein frames. Exploiting results already known in the Einstein frame, we give expressions for the power spectrum, spectral tilt and non-gaussianity associated with the Jordan frame curvature perturbation. In the case that an adiabatic limit has not been reached, we find that in general these quantities differ from those associated with the Einstein frame curvature perturbation, and also confirm their equivalence in the absence of isocurvature modes. We then proceed to consider two analytically soluble examples, the first involving a non-minimally coupled 'spectator' field and the second being a non-minimally coupled extension of the multi-brid inflation model. In the first model we find that predictions can easily be brought into agreement with the recent Planck results, as the tensor-to-scalar ratio is generally small, the spectral tilt tuneable and the non-gaussianity suppressed. In the second model we find that predictions for all three parameters can differ substantially from those predicted in the minimally coupled case, and that the recent Planck results for the spectral tilt can be used to constrain the non-minimal coupling parameters.
Non-linear curvature perturbation in multi-field inflation models with non-minimal coupling
NASA Astrophysics Data System (ADS)
White, Jonathan; Minamitsuji, Masato; Sasaki, Misao
2013-09-01
Using the δN formalism we consider the non-linear curvature perturbation in multi-field models of inflation with non-minimal coupling. In particular, we focus on the relation between the δN formalism as applied in the conformally related Jordan and Einstein frames. Exploiting results already known in the Einstein frame, we give expressions for the power spectrum, spectral tilt and non-gaussianity associated with the Jordan frame curvature perturbation. In the case that an adiabatic limit has not been reached, we find that in general these quantities differ from those associated with the Einstein frame curvature perturbation, and also confirm their equivalence in the absence of isocurvature modes. We then proceed to consider two analytically soluble examples, the first involving a non-minimally coupled `spectator' field and the second being a non-minimally coupled extension of the multi-brid inflation model. In the first model we find that predictions can easily be brought into agreement with the recent Planck results, as the tensor-to-scalar ratio is generally small, the spectral tilt tuneable and the non-gaussianity suppressed. In the second model we find that predictions for all three parameters can differ substantially from those predicted in the minimally coupled case, and that the recent Planck results for the spectral tilt can be used to constrain the non-minimal coupling parameters.
Gotoh, Hideki Sanada, Haruki; Yamaguchi, Hiroshi; Sogawa, Tetsuomi
2014-10-15
Optical nonlinear effects are examined using a two-color micro-photoluminescence (micro-PL) method in a coherently coupled exciton-biexciton system in a single quantum dot (QD). PL and photoluminescence excitation spectroscopy (PLE) are employed to measure the absorption spectra of the exciton and biexciton states. PLE for Stokes and anti-Stokes PL enables us to clarify the nonlinear optical absorption properties in the lowest exciton and biexciton states. The nonlinear absorption spectra for excitons exhibit asymmetric shapes with peak and dip structures, and provide a distinct contrast to the symmetric dip structures of conventional nonlinear spectra. Theoretical analyses with a density matrix method indicate that the nonlinear spectra are caused not by a simple coherent interaction between the exciton and biexciton states but by coupling effects among exciton, biexciton and continuum states. These results indicate that Fano quantum interference effects appear in exciton-biexciton systems at QDs and offer important insights into their physics.
Coexistence of synchrony and incoherence in oscillatory media under nonlinear global coupling
NASA Astrophysics Data System (ADS)
Schmidt, Lennart; Schönleber, Konrad; Krischer, Katharina; García-Morales, Vladimir
2014-03-01
We report a novel mechanism for the formation of chimera states, a peculiar spatiotemporal pattern with coexisting synchronized and incoherent domains found in ensembles of identical oscillators. Considering Stuart-Landau oscillators, we demonstrate that a nonlinear global coupling can induce this symmetry breaking. We find chimera states also in a spatially extended system, a modified complex Ginzburg-Landau equation. This theoretical prediction is validated with an oscillatory electrochemical system, the electro-oxidation of silicon, where the spontaneous formation of chimeras is observed without any external feedback control.
A semi-discrete integrable multi-component coherently coupled nonlinear Schrödinger system
NASA Astrophysics Data System (ADS)
Zhao, Hai-qiong; Yuan, Jinyun
2016-07-01
A new integrable semi-discrete version is proposed for the multi-component coherently coupled nonlinear Schrödinger equation. The integrability of the semi-discrete system is confirmed by existence of Lax pair and infinite number of conservation laws. With the aid of gauge transformations, explicit formulas for N-fold Darboux transformations are derived whereby some physically important solutions of the system are presented. Furthermore, the theory of the semi-discrete system including Lax pair, Darboux transformations, exact solutions and infinite number of conservation laws are shown for their continuous counterparts in the continuous limit.
Coexistence of synchrony and incoherence in oscillatory media under nonlinear global coupling
Schmidt, Lennart; García-Morales, Vladimir; Schönleber, Konrad; Krischer, Katharina
2014-03-15
We report a novel mechanism for the formation of chimera states, a peculiar spatiotemporal pattern with coexisting synchronized and incoherent domains found in ensembles of identical oscillators. Considering Stuart-Landau oscillators, we demonstrate that a nonlinear global coupling can induce this symmetry breaking. We find chimera states also in a spatially extended system, a modified complex Ginzburg-Landau equation. This theoretical prediction is validated with an oscillatory electrochemical system, the electro-oxidation of silicon, where the spontaneous formation of chimeras is observed without any external feedback control.
Rojas-Martínez, Mónica; Alonso, Joan F; Chaler, Joaquim; Mañanas, Miquel A
2013-01-01
Isokinetic exercises have been extensively used in order to analyze muscle imbalances and changes associated with fatigue. It is known that such changes are difficult to assess from EMG signals during dynamic contractions, especially, using linear signal processing tools. The aim of this work was to use nonlinear prediction in order to analyze muscle couplings and interactions in this context and to assess the load-sharing of different muscles during fatigue. Results show promising for detecting interaction strategies between muscles and even for the interaction between muscles and the output torque during endurance tests. PMID:24110859
Peng, Mingshu; Yang, Xiaozhong
2010-03-01
A detailed analysis of zero distributions in a special polynomial of the form lambda(tau)(lambda-a(1))(lambda-a(2))...(lambda-a(n))-(c+id) is proposed, where all a(i)(i=1,2,...,) have the same sign. As its applications, new criteria for asymptotic behavior of nonlinear delayed coupled systems with different topological structures are established. All possible bifurcations, including codimension-two bifurcations with 1:4/1:3 strong resonance in such a delayed difference system, are discussed. Numerical simulation gives a solid verification of the theoretical analysis. PMID:20370280
NASA Astrophysics Data System (ADS)
Peng, Mingshu; Yang, Xiaozhong
2010-03-01
A detailed analysis of zero distributions in a special polynomial of the form λτ(λ -a1)(λ -a2)⋯(λ -an)-(c +id) is proposed, where all ai(i =1,2,…,) have the same sign. As its applications, new criteria for asymptotic behavior of nonlinear delayed coupled systems with different topological structures are established. All possible bifurcations, including codimension-two bifurcations with 1:4/1:3 strong resonance in such a delayed difference system, are discussed. Numerical simulation gives a solid verification of the theoretical analysis.
NASA Astrophysics Data System (ADS)
Wang, Bohui; Wang, Jingcheng; Zhang, Langwen; Ge, Yang
2016-04-01
This paper studies the joining consensus of networked multi-agent systems subject to nonlinear couplings and weighted directed graphs via pinning control. A weighted-average consensus protocol is proposed to achieve the collective decision by interacting with the local information of some pinned agents. By proposing a novel joining consensus protocol, average consensus and general consensus strategies are joined to achieve an agreement for the weighting networked system. Furthermore, by calculating a proper consensus gain and using finite control Lyapunov controllers, an efficient joining consensus protocol is presented to improve the consensus speed. Sufficient conditions for achieving the consensuses asymptotically are proved. Finally, theoretical results are validated via simulations.
Nonlinear nanomechanical resonators for quantum optoelectromechanics
NASA Astrophysics Data System (ADS)
Rips, S.; Wilson-Rae, I.; Hartmann, M. J.
2014-01-01
We present a scheme for tuning and controlling nanomechanical resonators by subjecting them to electrostatic gradient fields, provided by nearby tip electrodes. We show that this approach enables access to a regime of optomechanics where the intrinsic nonlinearity of the nanoresonator can be explored. In this regime, one or several laser-driven cavity modes coupled to the nanoresonator and suitably adjusted gradient fields make it possible to control the motional state of the nanoresonator at the single-phonon level. Some applications of this platform have been presented previously [S. Rips, M. Kiffner, I. Wilson-Rae, and M. J. Hartmann, New J. Phys. 14, 023042 (2012), 10.1088/1367-2630/14/2/023042; S. Rips and M. J. Hartmann, Phys. Rev. Lett. 110, 120503 (2013), 10.1103/PhysRevLett.110.120503]. Here we provide a detailed description of the corresponding setup and its optomechanical coupling mechanisms together with an in-depth analysis of possible sources of damping or decoherence and a discussion of the readout of the nanoresonator state.
The Hall dynamo effect and nonlinear mode coupling during sawtooth magnetic reconnection
Ding, W. X.; Brower, D. L.; Deng, B. H.; Almagri, A. F.; Craig, D.; Fiksel, G.; Mirnov, V.; Prager, S. C.; Sarff, J. S.; Svidzinski, V.
2006-11-15
During magnetic reconnection associated with sawtooth activity in a reversed field pinch, we observe a large fluctuation-induced Hall electromotive force, <{delta}Jx{delta}B>/n{sub e}e, which is capable of modifying the equilibrium current. This Hall dynamo effect is determined in the hot plasma core by laser Faraday rotation which measures equilibrium and fluctuating magnetic field and current density. We find that the Hall dynamo is strongest when nonlinear mode coupling between three spatial Fourier modes of the resistive tearing instability is present. Mode coupling alters the phase relation between magnetic and current density fluctuations for individual Fourier modes leading to a finite Hall effect. Detailed measurements of the spatial and temporal dynamics for the dominant core resonant mode under various plasma configurations are described providing evidence regarding the origin of the Hall dynamo.
Deterministic escape dynamics of two-dimensional coupled nonlinear oscillator chains.
Fugmann, S; Hennig, D; Schimansky-Geier, L; Hänggi, P
2008-06-01
We consider the deterministic escape dynamics of a chain of coupled oscillators under microcanonical conditions from a metastable state over a cubic potential barrier. The underlying dynamics is conservative and noise free. We introduce a two-dimensional chain model and assume that neighboring units are coupled by Morse springs. It is found that, starting from a homogeneous lattice state, due to the nonlinearity of the external potential the system self-promotes an instability of its initial preparation and initiates complex lattice dynamics leading to the formation of localized large amplitude breathers, evolving in the direction of barrier crossing, accompanied by global oscillations of the chain transverse to the barrier. A few chain units accumulate locally sufficient energy to cross the barrier. Eventually the metastable state is left and either these particles dissociate or pull the remaining chain over the barrier. We show this escape for both linear rodlike and coil-like configurations of the chain in two dimensions. PMID:18643245
MOOSE: A parallel computational framework for coupled systems of nonlinear equations.
Derek Gaston; Chris Newman; Glen Hansen; Damien Lebrun-Grandie
2009-10-01
Systems of coupled, nonlinear partial differential equations (PDEs) often arise in simulation of nuclear processes. MOOSE: Multiphysics Object Oriented Simulation Environment, a parallel computational framework targeted at the solution of such systems, is presented. As opposed to traditional data-flow oriented computational frameworks, MOOSE is instead founded on the mathematical principle of Jacobian-free Newton-Krylov (JFNK) solution methods. Utilizing the mathematical structure present in JFNK, physics expressions are modularized into `Kernels,'' allowing for rapid production of new simulation tools. In addition, systems are solved implicitly and fully coupled, employing physics based preconditioning, which provides great flexibility even with large variance in time scales. A summary of the mathematics, an overview of the structure of MOOSE, and several representative solutions from applications built on the framework are presented.
Vibrational spectroscopy of a harmonic oscillator system nonlinearly coupled to a heat bath
NASA Astrophysics Data System (ADS)
Kato, Tsuyoshi; Tanimura, Yoshitaka
2002-10-01
Vibrational relaxation of a harmonic oscillator nonlinearly coupled to a heat bath is investigated by the Gaussian-Markovian quantum Fokker-Planck equation approach. The system-bath interaction is assumed to be linear in the bath coordinate, but linear plus square in the system coordinate modeling the elastic and inelastic relaxation mechanisms. Interplay of the two relaxation processes induced by the linear-linear and square-linear interactions in Raman or infrared spectra is discussed for various system-bath couplings, temperatures, and correlation times for the bath fluctuations. The one-quantum coherence state created through the interaction with the pump laser pulse relaxes through different pathways in accordance with the mechanisms of the system-bath interactions. Relations between the present theory, Redfield theory, and stochastic theory are also discussed.
NASA Astrophysics Data System (ADS)
Groeblacher, Simon; Wieczorek, Witlef; Christ, Peter; Buehler, Matthias; Wernicke, Doreen; Hoehne, Jens; Aspelmeyer, Markus
2011-03-01
We report on the operation of a closed-cycle dilution refrigerator for quantum optomechanics experiments at 25mK. The dilution fridge is accessible both via free-space as well as fiber coupling, allowing us to perform a variety of optical experiments at low temperatures. It is designed to vibrationally isolate the experiment allowing for stable operation of a high-finesse optical cavity. This enables us to perform cavity-optomechanics experiments at ultra-low temperatures.
NASA Astrophysics Data System (ADS)
Hasan, Md Arif
In this dissertation, we aim to analyze the strongly nonlinear dynamics of coupled ordered granular media and investigate interesting response regimes such as, passive wave redirection / redistribution and targeted energy transfer (TET). These studies are performed using numerical computations, analytical calculations, and experimental tests. In particular, we consider weakly coupled granular chains with or without on-site potentials, as well as two-dimensional granular networks with regularly placed intruders that act as effective coupling elements. Unlike previous studies of weakly coupled oscillatory chains, the dynamical systems considered herein incorporate both non-smooth effects due to possible separations between interacting neighboring beads (granules), as well as strongly nonlinear inter-particle Hertzian interactions. We show that these systems exhibit very rich and complex dynamics that, however, can be completely captured by our analytical approximations. For the case of weakly interacting granular networks, three independent mechanisms of efficient transport of energy from one chain to another are found. The first mechanism is a simple exchange of energy between the weakly interacting granular chains providing equi-partition of Nesterenko solitary waves through the chains. The second mechanism is a complete and recurrent exchange of energy (beating phenomenon) between the propagating breathers through the weakly coupled granular chains laying on a strong elastic foundation. The last mechanism is the most intriguing one and demonstrates targeted (irreversible) energy transfer between coupled granular chains due to appropriate stratification of their elastic foundations, in a macroscopic analogue of the well-known Landau-Zener Quantum effect in space. The aforementioned mechanisms of energy transfer and redirection in highly nonlinear granular chains are conceptually new and were presented for the first time. Analytical and computational studies of
Optomechanical accelerometers and gravity gradiometers
NASA Astrophysics Data System (ADS)
Guzman, Felipe
2016-04-01
Compact optical cavities can be combined with highly stable mechanical oscillators to yield accelerometers and gravity gradiometers of exquisite sensitivity, which are also traceable to the SI. We have incorporated Fabry-Pérot fiber-optic micro-cavities onto low-loss monolithic fused-silica mechanical oscillators for gradiometry, acceleration, and force sensing. These devices consist solely of a glass oscillator and fiber optics to inject and read out the coherent optical signal, making them very simple and compatible with space applications. We have demonstrated displacement sensitivities better than 200 am/√Hz with these fiber-optic micro-sensors. This translates into broadband acceleration noise floors below 100 nano-g/√Hz over a 10kHz, when combined with compact high frequency mechanical oscillators. Similarly, we have developed monolithic oscillators with resonance frequencies near and below 10 Hz, yielding measurement sensitivities better than 10‑9 m/s2. We will introduce our sensor concepts and present results on our fiber-optic displacement sensors and novel optomechanical devices.
NASA Astrophysics Data System (ADS)
Grill, M.; Radovan, M.; Melchiorri, R.; Slanger, T. G.
2009-12-01
The Compact Echelle Spectrograph for Aeronomical Research (CESAR) covers the wavelength range from 300 to 1000 nm with a spectral resolution of 20,000. It is being constructed at SRI International with funds from the National Science Foundation's Major Research Instrumentation Program. Our goal is to significantly expand the range of upper atmospheric science investigations (nightglow, aurora, and dayglow emissions) by providing to aeronomers a high-throughput, high-dispersion, large-passband spectrograph by scaling an astronomical grade echelle spectrograph into a portable version capable of siting at multiple geophysically significant stations, heretofore only available to astronomers at a handful of large observatories. We present major aspects of the ongoing opto-mechanical design. The design incorporates lessons learned from the construction of the High Resolution Echelle Spectrometer (HiRES) and the Automated Planet Finder (APF) spectrometer, amongst others. All major optical components are mounted on kinematically fully determined hexapod structures, giving unprecedented three-dimensional adjustment capability. CESAR is designed to operate in an outdoors environment in remote locations such as the Poker Flat Research Range (PFRR) in Alaska. We present an enclosure concept that will allow CESAR to withstand the weather conditions found at such sites while still giving CESAR's fore-optics full access to the sky.
The non-linear coupled spin 2-spin 3 Cotton equation in three dimensions
NASA Astrophysics Data System (ADS)
Linander, Hampus; Nilsson, Bengt E. W.
2016-07-01
In the context of three-dimensional conformal higher spin theory we derive, in the frame field formulation, the full non-linear spin 3 Cotton equation coupled to spin 2. This is done by solving the corresponding Chern-Simons gauge theory system of equations, that is, using F = 0 to eliminate all auxiliary fields and thus expressing the Cotton equation in terms of just the spin 3 frame field and spin 2 covariant derivatives and tensors (Schouten). In this derivation we neglect the spin 4 and higher spin sectors and approximate the star product commutator by a Poisson bracket. The resulting spin 3 Cotton equation is complicated but can be related to linearized versions in the metric formulation obtained previously by other authors. The expected symmetry (spin 3 "translation", "Lorentz" and "dilatation") properties are verified for Cotton and other relevant tensors but some perhaps unexpected features emerge in the process, in particular in relation to the non-linear equations. We discuss the structure of this non-linear spin 3 Cotton equation but its explicit form is only presented here, in an exact but not completely refined version, in appended files obtained by computer algebra methods. Both the frame field and metric formulations are provided.
NASA Astrophysics Data System (ADS)
Taghipour, Javad; Dardel, Morteza
2015-10-01
Steady state dynamical behavior of two degrees of freedom (DOF) system composed of a harmonically excited nonlinear oscillator coupled with a single DOF nonlinear energy sink (NES) is studied in comparison with the behavior of a system consisting of a nonlinear oscillator coupled with a two-DOF NES subjected to external harmonic excitation. First, an optimized set of parameters was obtained using optimization for the two-DOF system. Results show that the system with one NES has low robustness to the changes of the parameters and external force. By adding a degree of freedom to the first system, the steady state behavior of the resulting three-DOF system was investigated. Conclusions illustrated that increasing the degrees of freedom of the NES would increase the robustness of the system to the changes in system parameters and amplitude of external force.
Dynamics of dipoles and vortices in nonlinearly coupled three-dimensional field oscillators
NASA Astrophysics Data System (ADS)
Driben, R.; Konotop, V. V.; Malomed, B. A.; Meier, T.
2016-07-01
The dynamics of a pair of harmonic oscillators represented by three-dimensional fields coupled with a repulsive cubic nonlinearity is investigated through direct simulations of the respective field equations and with the help of the finite-mode Galerkin approximation (GA), which represents the two interacting fields by a superposition of 3 +3 harmonic-oscillator p -wave eigenfunctions with orbital and magnetic quantum numbers l =1 and m =1 , 0, -1 . The system can be implemented in binary Bose-Einstein condensates, demonstrating the potential of the atomic condensates to emulate various complex modes predicted by classical field theories. First, the GA very accurately predicts a broadly degenerate set of the system's ground states in the p -wave manifold, in the form of complexes built of a dipole coaxial with another dipole or vortex, as well as complexes built of mutually orthogonal dipoles. Next, pairs of noncoaxial vortices and/or dipoles, including pairs of mutually perpendicular vortices, develop remarkably stable dynamical regimes, which feature periodic exchange of the angular momentum and periodic switching between dipoles and vortices. For a moderately strong nonlinearity, simulations of the coupled-field equations agree very well with results produced by the GA, demonstrating that the dynamics is accurately spanned by the set of six modes limited to l =1 .
Dynamics of dipoles and vortices in nonlinearly coupled three-dimensional field oscillators.
Driben, R; Konotop, V V; Malomed, B A; Meier, T
2016-07-01
The dynamics of a pair of harmonic oscillators represented by three-dimensional fields coupled with a repulsive cubic nonlinearity is investigated through direct simulations of the respective field equations and with the help of the finite-mode Galerkin approximation (GA), which represents the two interacting fields by a superposition of 3+3 harmonic-oscillator p-wave eigenfunctions with orbital and magnetic quantum numbers l=1 and m=1, 0, -1. The system can be implemented in binary Bose-Einstein condensates, demonstrating the potential of the atomic condensates to emulate various complex modes predicted by classical field theories. First, the GA very accurately predicts a broadly degenerate set of the system's ground states in the p-wave manifold, in the form of complexes built of a dipole coaxial with another dipole or vortex, as well as complexes built of mutually orthogonal dipoles. Next, pairs of noncoaxial vortices and/or dipoles, including pairs of mutually perpendicular vortices, develop remarkably stable dynamical regimes, which feature periodic exchange of the angular momentum and periodic switching between dipoles and vortices. For a moderately strong nonlinearity, simulations of the coupled-field equations agree very well with results produced by the GA, demonstrating that the dynamics is accurately spanned by the set of six modes limited to l=1. PMID:27575123
NASA Astrophysics Data System (ADS)
Lakshmanan, M.; Sahadevan, R.
1993-03-01
In recent investigations on nonlinear dynamics, the singularity structure analysis pioneered by Kovalevskaya, Painlevé and contempories, which stresses the meromorphic nature of the solutions of the equations of motion in the complex-time plane, is found to play an increasingly important role. Particularly, soliton equations have been found to be associated with the so-called Painlevé property, which implies that the solutions are free from movable critical points/manifolds. Finite-dimensional integrable dynamical systems have also been found to possess such a property. In this review, after briefly presenting the historical developments and various features of the Painlevé (P) method, we demonstrate how it provides an effective tool in the analysis of nonlinear dynamical systems, starting from simple examples. We apply this method to several important coupled nonlinear oscillators governed by generic Hamiltonians of polynomial type with two, three and arbitrary ( N) degrees of freedom and classify all the P-cases. Sufficient numbers of involutive integrals of motion for each of the P-cases are constructed by employing other direct methods. In particular, we examine the question of integrability from the viewpoint of symmetries, explicitly demonstrate the existence of nontrivial extended Lie symmetries for the P-cases, and obtain the required integrals of motion by direct integration of symmetries. Furthermore, we briefly explain how the singularity structure analysis can be used to understand some of the intrinsic properties of nonintegrability and chaos with special reference to the two-coupled quartic anharmonic oscillators and Henon-Heiles systems.
NASA Astrophysics Data System (ADS)
Tiwari, R. K.; Rajesh, Rekapalli; Padmavathi, B.
2015-02-01
Significant fluctuations have been observed in Indian temperatures during past century. In order to identify the statistical periodicities in the maximum and minimum temperature data of different Indian zones, we have spectrally and statistically analyzed the homogeneous regional temperature series from the Western Himalayas, the Northern West, the North Central, the North East (NE), the West Coast, the East Coast, and the Interior Peninsula for the period of 107 years spanning over 1901-2007 using the multitaper method (MTM) and singular spectrum analysis (SSA) methods. The first SSA reconstructed the principal component of all the data sets representing a nonlinear trend (indicating a monotonic rise in temperature probably due to greenhouse gases and other forcing) that varies from region to region. We have reconstructed the temperature time series using the second to tenth oscillatory principal components of all the eight regions and computed their power spectral density using MTM. Our analyses indicate that there is a strong spectral power in the period range of 2-7 years and 53 years, which are matched respectively with the known El Niño-Southern oscillation (ENSO) periods and ocean circulation cycles. Further, the spectral analysis also revealed a statistically significant but riven cycle in a period range of 9.8-13 years corresponding to the Schwabe cycle in all Indiaian maximum and minimum temperature records and almost all the zonal records except in the NE data. In some of the cases, the 22 year double sunspot (Hale cycle) cycle was also identified here. Invariably the splitting of spectral peaks corresponding to solar signal indicated nonlinear characteristics of the data and; therefore, even small variations in the solar output may help in catalyzing the coupled El Niño-atmospheric ENSO cycles by altering the solar heat input to the oceans. We, therefore, conclude that the Indian temperature variability is probably driven by the nonlinear coupling of
Sahyoun, Walaa; Duchamp, Jean-Marc; Benech, Philippe
2011-10-01
Coupled resonator filters (CRFs) are the new generation of BAW filters recently designed for the front-end modules of mobile transmission systems. Looking for designers' requirements, CRF devices have been characterized and modeled. The model based on equivalent circuits relies on material constants such as stiffness and electro-coupling coefficients, and works only for linear-mode propagation. Because of their positions between antennas and power amplifiers, they often work under high RF power, inducing nonlinear response in the AlN piezoelectric layer. In this work, we analyze for the first time the nonlinear behavior of AlN material particularly for coupled BAW resonators. To characterize the nonlinear effects in CRFs, we measure the 1-dB gain compression point (P1dB) and the intercept point (IP(3)). Then, we develop a nonlinear model of CRFs using harmonic balance (HB) simulation in commercially available software. The HB environment allows fitting simulations to measurements in terms of P(1dB) and IP(3). We find that a high RF power induces nonlinear changes in the material constants' real parts: elastic stiffness c(33) (4.9%), piezoelectric e(33) (17.4%), and permittivity ϵ(33) (5.2%). These nonlinear variations of material constants describe the nonlinear behavior of CRF devices using the same deposit process for AlN material. PMID:21989879
Einstein-Podolsky-Rosen paradox and quantum steering in a three-mode optomechanical system
NASA Astrophysics Data System (ADS)
He, Qiongyi; Ficek, Zbigniew
2014-02-01
We study multipartite entanglement, the generation of Einstein-Podolsky-Rosen (EPR) states, and quantum steering in a three-mode optomechanical system composed of an atomic ensemble located inside a single-mode cavity with a movable mirror. The cavity mode is driven by a short laser pulse, has a nonlinear parametric-type interaction with the mirror and a linear beam-splitter-type interaction with the atomic ensemble. There is no direct interaction of the mirror with the atomic ensemble. A threshold effect for the dynamics of the system is found, above which the system works as an amplifier and below which as an attenuator of the output fields. The threshold is determined by the ratio of the coupling strengths of the cavity mode to the mirror and to the atomic ensemble. It is shown that above the threshold, the system effectively behaves as a two-mode system in which a perfect bipartite EPR state can be generated, while it is impossible below the threshold. Furthermore, a fully inseparable tripartite entanglement and even further a genuine tripartite entanglement can be produced above and below the threshold. In addition, we consider quantum steering and examine the monogamy relations that quantify the amount of bipartite steering that can be shared between different modes. It is found that the mirror is more capable for steering of entanglement than the cavity mode. The two-way steering is found between the mirror and the atomic ensemble despite the fact that they are not directly coupled to each other, while it is impossible between the output of cavity mode and the ensemble which are directly coupled to each other.
Noise-induced transitions in optomechanical synchronization
NASA Astrophysics Data System (ADS)
Weiss, Talitha; Kronwald, Andreas; Marquardt, Florian
2016-01-01
We study how quantum and thermal noise affects synchronization of two optomechanical limit-cycle oscillators. Classically, in the absence of noise, optomechanical systems tend to synchronize either in-phase or anti-phase. Taking into account the fundamental quantum noise, we find a regime where fluctuations drive transitions between these classical synchronization states. We investigate how this ‘mixed’ synchronization regime emerges from the noiseless system by studying the classical-to-quantum crossover and we show how the time scales of the transitions vary with the effective noise strength. In addition, we compare the effects of thermal noise to the effects of quantum noise.
Hybrid Quantum Optomechanics with Graphene Nanoresonators
NASA Astrophysics Data System (ADS)
Shaffer, Airlia; Bhat, Ajay K.; Patil, Yogesh Sharad; Bhave, Sunil; Vengalattore, Mukund
2015-05-01
We report on the realization of a hybrid quantum system consisting of a graphene nanoresonator coupled to an ultracold spin ensemble. This work is motivated by the large quantum nonlinearities inherent to graphene resonators, as well as the strong atom-resonator coupling due to their commensurate mass ratio. We fabricate micromechanical suspended graphene membrane resonators and study their properties, both through spectroscopic and interferometric imaging. With dark field images, we relate the nonlinear intermode coupling in graphene to the quality factors of the modes. This work provides a foundation for the studies of entanglement between a macroscopic graphene membrane and an auxiliary quantum system of ultracold atoms. Additionally, such graphene resonators can be used for force, position, and mass sensing in the quantum limit. This work is supported by the DARPA QuASAR program through a grant from the ARO and an NSF INSPIRE award.
Dissipative Optomechanical Preparation of Macroscopic Quantum Superposition States.
Abdi, M; Degenfeld-Schonburg, P; Sameti, M; Navarrete-Benlloch, C; Hartmann, M J
2016-06-10
The transition from quantum to classical physics remains an intensely debated question even though it has been investigated for more than a century. Further clarifications could be obtained by preparing macroscopic objects in spatial quantum superpositions and proposals for generating such states for nanomechanical devices either in a transient or a probabilistic fashion have been put forward. Here, we introduce a method to deterministically obtain spatial superpositions of arbitrary lifetime via dissipative state preparation. In our approach, we engineer a double-well potential for the motion of the mechanical element and drive it towards the ground state, which shows the desired spatial superposition, via optomechanical sideband cooling. We propose a specific implementation based on a superconducting circuit coupled to the mechanical motion of a lithium-decorated monolayer graphene sheet, introduce a method to verify the mechanical state by coupling it to a superconducting qubit, and discuss its prospects for testing collapse models for the quantum to classical transition. PMID:27341233
Dissipative Optomechanical Preparation of Macroscopic Quantum Superposition States
NASA Astrophysics Data System (ADS)
Abdi, M.; Degenfeld-Schonburg, P.; Sameti, M.; Navarrete-Benlloch, C.; Hartmann, M. J.
2016-06-01
The transition from quantum to classical physics remains an intensely debated question even though it has been investigated for more than a century. Further clarifications could be obtained by preparing macroscopic objects in spatial quantum superpositions and proposals for generating such states for nanomechanical devices either in a transient or a probabilistic fashion have been put forward. Here, we introduce a method to deterministically obtain spatial superpositions of arbitrary lifetime via dissipative state preparation. In our approach, we engineer a double-well potential for the motion of the mechanical element and drive it towards the ground state, which shows the desired spatial superposition, via optomechanical sideband cooling. We propose a specific implementation based on a superconducting circuit coupled to the mechanical motion of a lithium-decorated monolayer graphene sheet, introduce a method to verify the mechanical state by coupling it to a superconducting qubit, and discuss its prospects for testing collapse models for the quantum to classical transition.
High-sensitivity three-mode optomechanical transducer
Zhao, C.; Fang, Q.; Susmithan, S.; Miao, H.; Ju, L.; Fan, Y.; Blair, D.; Hosken, D. J.; Munch, J.; Veitch, P. J.; Slagmolen, B. J. J.
2011-12-15
Three-mode optomechanical interactions have been predicted to allow the creation of very high sensitivity transducers in which very strong optical self-cooling and strong optomechanical quantum entanglement are predicted. Strong coupling is achieved by engineering a transducer in which both the pump laser and a single signal sideband frequency are resonantly enhanced. Here we demonstrate that very high sensitivity can be achieved in a very simple system consisting of a Fabry-Perot cavity with CO{sub 2} laser thermal tuning. We demonstrate a displacement sensitivity of {approx}1x10{sup -17} m/{radical}(Hz), which is sufficient to observe a thermally excited acoustic mode in a 5.6 kg sapphire mirror with a signal-to-noise ratio of more than 20 dB. It is shown that a measurement sensitivity of {approx}2x10{sup -20} m/{radical}(Hz) limited by the quantum shot noise is achievable with optimization of the cavity parameters.
NASA Astrophysics Data System (ADS)
Vakhnenko, Oleksiy O.
2016-05-01
The variativity of governing coupling parameters in the integrable nonlinear Schrödinger system on a triangular-lattice ribbon is shown to ensure the important qualitative rearrangements in the system dynamics. There are at least the two types of system crucial modifications stipulated by the two types of governing parameters. Thus the longitudinal coupling parameters regulated mainly by the background values of concomitant field variables are responsible for the bifurcation of primary integrable nonlinear system into the integrable nonlinear system of Ablowitz-Ladik type. As a consequence in a critical point the number of independent field variables is reduced by a half and the system Poisson structure turns out to be degenerate. On the other hand the transverse coupling parameters regulated basically by the choice of their a priori arbitrary dependencies on time are capable to incorporate the effect of external linear potential. As a consequence the primary integrable nonlinear system with appropriately adjusted parametrical driving becomes isomorphic to the system modeling the Bloch oscillations of charged nonlinear carriers in an electrically biased ribbon of triangular lattice. The multi-component structure of basic integrable system alongside with the attractive character of system nonlinearities has predetermined the logic of whole consideration.
Sokhoyan, R.; Azizbekyan, H.; Leroy, C.; Ishkhanyan, A.
2011-04-15
We discuss the strong-coupling regime of the nonlinear Landau-Zener problem occurring at coherent photo- and magneto-association of ultracold atoms. We apply a variational approach to an exact third-order nonlinear differential equation for the molecular state probability and construct an accurate approximation describing the time dynamics of the coupled atom-molecule system. The resultant solution improves the accuracy of the previous approximation [22]. The obtained results reveal a remarkable observation that in the strong-coupling limit, the resonance crossing is mostly governed by the nonlinearity, while the coherent atom-molecule oscillations occurring soon after crossing the resonance are principally of a linear nature. This observation is supposedly general for all nonlinear quantum systems having the same generic quadratic nonlinearity, due to the basic attributes of the resonance crossing processes in such systems. The constructed approximation turns out to have a larger applicability range than it was initially expected, covering the whole moderate-coupling regime for which the proposed solution accurately describes ail the main characteristics of the system evolution except the amplitude of the coherent atom-molecule oscillation, which is rather overestimated.
A nonlinear impulse response model of the coupled carbon cycle-climate system (NICCS)
NASA Astrophysics Data System (ADS)
Hooss, G.; Voss, R.; Hasselmann, K.; Maier-Reimer, E.; Joos, F.
Impulse-response-function (IRF) models are designed for applications requiring a large number of climate change simulations, such as multi-scenario climate impact studies or cost-benefit integrated-assessment studies. The models apply linear response theory to reproduce the characteristics of the climate response to external forcing computed with sophisticated state-of-the-art climate models like general circulation models of the physical ocean-atmosphere system and three-dimensional oceanic-plus-terrestrial carbon cycle models. Although highly computer efficient, IRF models are nonetheless capable of reproducing the full set of climate-change information generated by the complex models against which they are calibrated. While limited in principle to the linear response regime (less than about 3∘C global-mean temperature change), the applicability of the IRF model presented has been extended into the nonlinear domain through explicit treatment of the climate system's dominant nonlinearities: CO2 chemistry in ocean water, CO2 fertilization of land biota, and sublinear radiative forcing. The resultant nonlinear impulse-response model of the coupled carbon cycle-climate system (NICCS) computes the temporal evolution of spatial patterns of climate change for four climate variables of particular relevance for climate impact studies: near-surface temperature, cloud cover, precipitation, and sea level. The space-time response characteristics of the model are derived from an EOF analysis of a transient 850-year greenhouse warming simulation with the Hamburg atmosphere-ocean general circulation model ECHAM3-LSG and a similar response experiment with the Hamburg carbon cycle model HAMOCC. The model is applied to two long-term CO2 emission scenarios, demonstrating that the use of all currently estimated fossil fuel resources would carry the Earth's climate far beyond the range of climate change for which reliable quantitative predictions are possible today, and that even a
Reprint of : Dynamics of coupled vibration modes in a quantum non-linear mechanical resonator
NASA Astrophysics Data System (ADS)
Labadze, G.; Dukalski, M.; Blanter, Ya. M.
2016-08-01
We investigate the behaviour of two non-linearly coupled flexural modes of a doubly clamped suspended beam (nanomechanical resonator). One of the modes is externally driven. We demonstrate that classically, the behavior of the non-driven mode is reminiscent of that of a parametrically driven linear oscillator: it exhibits a threshold behavior, with the amplitude of this mode below the threshold being exactly zero. Quantum-mechanically, we were able to access the dynamics of this mode below the classical parametric threshold. We show that whereas the mean displacement of this mode is still zero, the mean squared displacement is finite and at the threshold corresponds to the occupation number of 1/2. This finite displacement of the non-driven mode can serve as an experimentally verifiable quantum signature of quantum motion.
NASA Astrophysics Data System (ADS)
Dymnikova, Irina; Galaktionov, Evgeny
2016-03-01
In nonlinear electrodynamics minimally coupled to gravity, regular spherically symmetric electrically charged solutions satisfy the weak energy condition and have obligatory de Sitter center. By the Gürses-Gürsey algorithm they are transformed to regular axially symmetric solutions asymptotically Kerr-Newman for a distant observer. Rotation transforms de Sitter center into de Sitter equatorial disk embedded as a bridge into a de Sitter vacuum surface. The de Sitter surfaces satisfy p = -ρ and have properties of a perfect conductor and ideal diamagnetic. The Kerr ring singularity is replaced with the superconducting current which serves as a non-dissipative electromagnetic source of the asymptotically Kerr-Newman geometry. Violation of the weak energy condition is prevented by the basic requirement of electrodynamics of continued media.
NASA Astrophysics Data System (ADS)
Zakeri, Gholam-Ali; Yomba, Emmanuel
2015-06-01
A generalized (2+1)-dimensional coupled cubic-quintic Ginzburg-Landau equation with higher-order nonlinearities is fully investigated for modulational instability regions. We obtained the constraints that allow the modulational instability (MI) procedure to transform the system under consideration into an analysis of the roots of a polynomial equation of the fourth degree. Because of the complexity of the dispersion relation and its dependence on many parameters, we study numerous examples that are presented graphically. A numerical simulation based on a split-step Fourier method is implemented on the above equation. In addition to the general case, we have considered some special cases that allow us to investigate the behavior of MI in different regions.
Zakeri, Gholam-Ali; Yomba, Emmanuel
2015-06-01
A generalized (2+1)-dimensional coupled cubic-quintic Ginzburg-Landau equation with higher-order nonlinearities is fully investigated for modulational instability regions. We obtained the constraints that allow the modulational instability (MI) procedure to transform the system under consideration into an analysis of the roots of a polynomial equation of the fourth degree. Because of the complexity of the dispersion relation and its dependence on many parameters, we study numerous examples that are presented graphically. A numerical simulation based on a split-step Fourier method is implemented on the above equation. In addition to the general case, we have considered some special cases that allow us to investigate the behavior of MI in different regions. PMID:26172769
NASA Astrophysics Data System (ADS)
Manevitch, Leonid I.; Kovaleva, Agnessa; Sigalov, Grigori
2016-03-01
In this paper we study the effect of nonstationary energy localization in a nonlinear conservative resonant system of two weakly coupled oscillators. This effect is alternative to the well-known stationary energy localization associated with the existence of localized normal modes and resulting from a local topological transformation of the phase portraits of the system. In this work we show that nonstationary energy localization results from a global transformation of the phase portrait. A key to solving the problem is the introduction of the concept of limiting phase trajectories (LPTs) corresponding to maximum possible energy exchange between the oscillators. We present two scenarios of nonstationary energy localization under the condition of 1:1 resonance. It is demonstrated that the conditions of nonstationary localization determine the conditions of efficient targeted energy transfer in a generating dynamical system. A possible extension to multi-particle systems is briefly discussed.
Effect of asymmetry parameter on the dynamical states of nonlocally coupled nonlinear oscillators
NASA Astrophysics Data System (ADS)
Gopal, R.; Chandrasekar, V. K.; Senthilkumar, D. V.; Venkatesan, A.; Lakshmanan, M.
2015-06-01
We show that coexisting domains of coherent and incoherent oscillations can be induced in an ensemble of any identical nonlinear dynamical systems using nonlocal rotational matrix coupling with an asymmetry parameter. Further, a chimera is shown to emerge in a wide range of the asymmetry parameter in contrast to near π/2 values of it employed in earlier works. We have also corroborated our results using the strength of incoherence in the frequency domain (Sω) and in the amplitude domain (S ), thereby distinguishing the frequency and amplitude chimeras. The robust nature of the asymmetry parameter in inducing chimeras in any generic dynamical system is established using ensembles of identical Rössler oscillators, Lorenz systems, and Hindmarsh-Rose neurons in their chaotic regimes.
MOOSE: A PARALLEL COMPUTATIONAL FRAMEWORK FOR COUPLED SYSTEMS OF NONLINEAR EQUATIONS.
G. Hansen; C. Newman; D. Gaston
2009-05-01
Systems of coupled, nonlinear partial di?erential equations often arise in sim- ulation of nuclear processes. MOOSE: Multiphysics Ob ject Oriented Simulation Environment, a parallel computational framework targeted at solving these systems is presented. As opposed to traditional data / ?ow oriented com- putational frameworks, MOOSE is instead founded on mathematics based on Jacobian-free Newton Krylov (JFNK). Utilizing the mathematical structure present in JFNK, physics are modularized into “Kernels” allowing for rapid production of new simulation tools. In addition, systems are solved fully cou- pled and fully implicit employing physics based preconditioning allowing for a large amount of ?exibility even with large variance in time scales. Background on the mathematics, an inspection of the structure of MOOSE and several rep- resentative solutions from applications built on the framework are presented.
Nonparametric identification of a class of nonlinear close-coupled dynamic systems
NASA Technical Reports Server (NTRS)
Udwadia, F. E.; Kuo, C. P.
1981-01-01
A nonparametric identification technique for the identification of close coupled dynamic systems with arbitrary memoryless nonlinearities is presented. The method utilizes noisy recorded data (acceleration, velocity and displacement) to identify the restoring forces in the system. The masses in the system are assumed to be known (or fairly well estimated from the design drawings). The restoring forces are expanded in a series of orthogonal polnomials and the coefficients of these polynomial expansions are obtained by using least square fit method. A particularly simple and computationally efficient method is proposed for dealing with separable restoring forces. The identified results are found to be relatively insensitive to measurement noise. An analysis of the effects of measurement noise on the quality of the estimates is given. The computations are shown to be relatively quick (when compared say to the Wiener identification method) and the core storage required relatively small, making the method suitable for onboard identification of large space structures.
Nonlinearly coupled, gain-switched Nd:YAG second harmonic laser with variable pulse width.
Ray, Aniruddha; Das, Susanta K; Mishra, Lokanath; Datta, Prasanta K; Saltiel, Soloman M
2009-02-01
An all-solid-state, gain-switched, green laser is developed using a side diode-array pumped Nd:YAG laser and a KTiOPO(4) (KTP) crystal as an intracavity frequency doubler. The effect of nonlinear coupling on the pulse width of the fundamental is studied and is found to be in good agreement with the experimental measurement. In this preliminary experiment, a peak power of 40 W at 532 nm corresponding to a pulse width of 409 ns is obtained for an average pump power of 2 W. Compared to a Q-switched laser, it is simple and does not require a high voltage RF driver or saturable absorbers in its operation. The laser may be useful where relatively longer nanosecond pulses are required such as eye surgery, micromachining, and underwater communication. PMID:19183606
Traveling wave solutions in a chain of periodically forced coupled nonlinear oscillators
NASA Astrophysics Data System (ADS)
Duanmu, M.; Whitaker, N.; Kevrekidis, P. G.; Vainchtein, A.; Rubin, J. E.
2016-06-01
Motivated by earlier studies of artificial perceptions of light called phosphenes, we analyze traveling wave solutions in a chain of periodically forced coupled nonlinear oscillators modeling this phenomenon. We examine the discrete model problem in its co-traveling frame and systematically obtain the corresponding traveling waves in one spatial dimension. Direct numerical simulations as well as linear stability analysis are employed to reveal the parameter regions where the traveling waves are stable, and these waves are, in turn, connected to the standing waves analyzed in earlier work. We also consider a two-dimensional extension of the model and demonstrate the robust evolution and stability of planar fronts. Our simulations also suggest the radial fronts tend to either annihilate or expand and flatten out, depending on the phase value inside and the parameter regime. Finally, we observe that solutions that initially feature two symmetric fronts with bulged centers evolve in qualitative agreement with experimental observations of phosphenes.
NASA Astrophysics Data System (ADS)
Soyarslan, C.; Bargmann, S.
2016-06-01
In this paper, we present a thermomechanical framework which makes use of the internal variable theory of thermodynamics for damage-coupled finite viscoplasticity with nonlinear isotropic hardening. Damage evolution, being an irreversible process, generates heat. In addition to its direct effect on material's strength and stiffness, it causes deterioration of the heat conduction. The formulation, following the footsteps of Simó and Miehe (1992), introduces inelastic entropy as an additional state variable. Given a temperature dependent damage dissipation potential, we show that the evolution of inelastic entropy assumes a split form relating to plastic and damage parts, respectively. The solution of the thermomechanical problem is based on the so-called isothermal split. This allows the use of the model in 2D and 3D example problems involving geometrical imperfection triggered necking in an axisymmetric bar and thermally triggered necking of a 3D rectangular bar.
NASA Astrophysics Data System (ADS)
Bouklas, Nikolaos; Landis, Chad M.; Huang, Rui
2015-06-01
Hydrogels are capable of coupled mass transport and large deformation in response to external stimuli. In this paper, a nonlinear, transient finite element formulation is presented for initial boundary value problems associated with swelling and deformation of hydrogels, based on a nonlinear continuum theory that is consistent with classical theory of linear poroelasticity. A mixed finite element method is implemented with implicit time integration. The incompressible or nearly incompressible behavior at the initial stage imposes a constraint to the finite element discretization in order to satisfy the Ladyzhenskaya-Babuska-Brezzi (LBB) condition for stability of the mixed method, similar to linear poroelasticity as well as incompressible elasticity and Stokes flow; failure to choose an appropriate discretization would result in locking and numerical oscillations in transient analysis. To demonstrate the numerical method, two problems of practical interests are considered: constrained swelling and flat-punch indentation of hydrogel layers. Constrained swelling may lead to instantaneous surface instability for a soft hydrogel in a good solvent, which can be regulated by assuming a stiff surface layer. Indentation relaxation of hydrogels is simulated beyond the linear regime under plane strain conditions, in comparison with two elastic limits for the instantaneous and equilibrium states. The effects of Poisson's ratio and loading rate are discussed. It is concluded that the present finite element method is robust and can be extended to study other transient phenomena in hydrogels.
Soliton interactions and complexes for coupled nonlinear Schrödinger equations.
Jiang, Yan; Tian, Bo; Liu, Wen-Jun; Sun, Kun; Li, Min; Wang, Pan
2012-03-01
Under investigation in this paper are the coupled nonlinear Schrödinger (CNLS) equations, which can be used to govern the optical-soliton propagation and interaction in such optical media as the multimode fibers, fiber arrays, and birefringent fibers. By taking the 3-CNLS equations as an example for the N-CNLS ones (N≥3), we derive the analytic mixed-type two- and three-soliton solutions in more general forms than those obtained in the previous studies with the Hirota method and symbolic computation. With the choice of parameters for those soliton solutions, soliton interactions and complexes are investigated through the asymptotic and graphic analysis. Soliton interactions and complexes with the bound dark solitons in a mode or two modes are observed, including that (i) the two bright solitons display the breatherlike structures while the two dark ones stay parallel, (ii) the two bright and dark solitons all stay parallel, and (iii) the states of the bound solitons change from the breatherlike structures to the parallel one even with the distance between those solitons smaller than that before the interaction with the regular one soliton. Asymptotic analysis is also used to investigate the elastic and inelastic interactions between the bound solitons and the regular one soliton. Furthermore, some discussions are extended to the N-CNLS equations (N>3). Our results might be helpful in such applications as the soliton switch, optical computing, and soliton amplification in the nonlinear optics. PMID:22587200
Testing methodologies for the nonlinear analysis of causal relationships in neurovascular coupling.
Lüdtke, Niklas; Logothetis, Nikos K; Panzeri, Stefano
2010-10-01
We investigated the use and implementation of a nonlinear methodology for establishing which changes in neurophysiological signals cause changes in the blood oxygenation level-dependent (BOLD) contrast measured in functional magnetic resonance imaging. Unlike previous analytical approaches, which used linear correlation to establish covariations between neural activity and BOLD, we propose a directed information-theoretic measure, the transfer entropy, which can elucidate even highly nonlinear causal relationships between neural activity and BOLD signal. In this study we investigated the practicality of such an analysis given the limited data samples that can be collected experimentally due to the low temporal resolution of BOLD signals. We implemented several algorithms for the estimation of transfer entropy and we tested their effectiveness using simulated local field potentials (LFPs) and BOLD data constructed to match the main statistical properties of real LFP and BOLD signals measured simultaneously in monkey primary visual cortex. We found that using the advanced methods of entropy estimation implemented and described here, a transfer entropy analysis of neurovascular coupling based on experimentally attainable data sets is feasible. PMID:20409664
Sensing of mechanical motion at the quantum level via a hybrid atom-optomechanical setup
NASA Astrophysics Data System (ADS)
Seok, Hyojun; Bariani, Francesco; Singh, Swati; Vengalattore, Mukund; Meystre, Pierre
2015-05-01
We consider a hybrid quantum system in which an optomechanical cavity is coupled to a Fabry-Pérot cavity containing a trapped cold atomic ensemble. We show that it is possible to cool the mechanics to the ground state from room temperature outside the resolved-sideband regime by optically coupling it to the internal levels of the atoms. We also find that while in the familiar homodyne detection of small displacements this system exhibits the same standard quantum limit as traditional cavity optomechanics, it is possible to engineer the optical response of the atoms so as to realize a back-action evading measurement scheme. We acknowledge financial support from NSF, ARO and the DARPA QuaSAR and ORCHID programs.
Lin, Tzy-Rong; Lin, Chiang-Hsin; Hsu, Jin-Chen
2015-01-01
We propose dynamic modulation of a hybrid plasmonic-photonic crystal nanocavity using monochromatic coherent acoustic phonons formed by ultrahigh-frequency surface acoustic waves (SAWs) to achieve strong optomechanical interaction. The crystal nanocavity used in this study consisted of a defective photonic crystal beam coupled to a metal surface with a nanoscale air gap in between and provided hybridization of a highly confined plasmonic-photonic mode with a high quality factor and deep subwavelength mode volume. Efficient photon-phonon interaction occurs in the air gap through the SAW perturbation of the metal surface, strongly coupling the optical and acoustic frequencies. As a result, a large modulation bandwidth and optical resonance wavelength shift for the crystal nanocavity are demonstrated at telecommunication wavelengths. The proposed SAW-based modulation within the hybrid plasmonic-photonic crystal nanocavities beyond the diffraction limit provides opportunities for various applications in enhanced sound-light interaction and fast coherent acoustic control of optomechanical devices. PMID:26346448
Applying a fully nonlinear particle filter on a coupled ocean-atmosphere climate model
NASA Astrophysics Data System (ADS)
Browne, Philip; van Leeuwen, Peter Jan; Wilson, Simon
2014-05-01
It is a widely held assumption that particle filters are not applicable in high-dimensional systems due to filter degeneracy, commonly called the curse of dimensionality. This is only true of naive particle filters, and indeed it has been shown much more advanced methods perform particularly well on systems of dimension up to 216 ≡ 6.5 × 104. In this talk we will present results from using the equivalent weights particle filter in twin experiments with the global climate model HadCM3. These experiments have a number of notable features. Firstly the sheer size of model in use is substantially larger than has been previously achieved. The model has state dimension approximately 4 × 106 and approximately 4 × 104 observations per analysis step. This is 2 orders of magnitude more than has been achieved with a particle filter in the geosciences. Secondly, the use of a fully nonlinear data assimilation technique to initialise a climate model gives us the possibility to find non-Gaussian estimates for the current state of the climate. In doing so we may find that the same model may demonstrate multiple likely scenarios for forecasts on a multi-annular/decadal timescale. The experiments consider to assimilating artificial sea surface temperatures daily for several years. We will discuss how an ensemble based method for assimilation in a coupled system avoids issues faced by variational methods. Practical details of how the experiments were carried out, specifically the use of the EMPIRE data assimilation framework, will be discussed. The results from applying the nonlinear data assimilation method can always be improved through having a better representation of the model error covariance matrix. We will discuss the representation which we have used for this matrix, and in particular, how it was generated from the coupled system.
All-electrical nonlinear fano resonance in coupled quantum point contacts
NASA Astrophysics Data System (ADS)
Xiao, Shiran
This thesis is motivated by recent interest in the Fano resonance (FR). As a wave-interference phenomenon, this resonance is of increasing importance in optics, plasmon-ics, and metamaterials, where its ability to cause rapid signal modulations under variation of some suitable parameter makes it desirable for a variety of applications. In this thesis, I focus on a novel manifestation of this resonance in systems of coupled quantum point contacts (QPCs). The major finding of this work is that the FR in this system may be ma-nipulated by applying a nonlinear DC bias to the system. Under such conditions, we are able to induce significant distortions of resonance lineshape, providing a pathway to all-electrical manipulation of the FR. To interpret this behavior we apply a recently-developed model for a three-path FR, involving an additional "intruder" continuum. We have previously used this model to account for the magnetic-field induced distortions of the FR observed in coupled QPCs, and show here that this model also provides a frame-work for understanding the observed nonlinear behavior. Our work therefore reveals a new manifestation of the FR that can be sensitively tailored by external control, a finding that may eventually allow the application of this feature to nanoelectronics. Since the in-terference scheme involves in this thesis is a completely general one, it should be broadly applicable across a variety of different wave-based systems, including those in both pho-tonics and electronics and opening up the possibility of new applications in areas such as chemical and biological sensing and secure communications.
Non-linear diffusion paths in two-phase ternary diffusion couples
NASA Astrophysics Data System (ADS)
Yang, Hongwei
2005-11-01
Prediction of diffusion paths facilitates the understanding of interdiffusion microstructure development at the vicinity of a common interface between two alloys. Understanding the influence of interdiffusion on microstructure is critically important to the design of many advanced materials systems such as high temperature coatings. The current study using DICTRA finite difference software predicts non-linear features formed on the diffusion path as the initial interface is approached. The non-linear diffusion path deviates from the linear zigzag shape predicted by an error function model for multiphase diffusion couples. The deviations appear as "horns" that protrude from the linear paths. The horns were found to be of two types. When the two outer legs of the diffusion path bend in the same direction, a "single-horn" is formed. When they bend in opposite directions a "double-horn" is formed. The formation of horns is attributed to the concentration dependence of the diffusivity. It results in a shift on the maximum of the flux profile from the initial interface, which accordingly leads to a rapid rise or decrease of the precipitate fraction as the interface is approached. It was found that the horn length is proportional to the composition vector component along the major eigenvector of the effective diffusivity matrix. Applying these results to a study on Ni-Cr-Al diffusion couples prepared from gamma + beta alloys, it also was found that the formation of single-phase beta layers could be attributed to the horns pointing away from each other, in which case the diffusion path could intersect the single phase beta region of the phase diagram. Comparison between EPMA data and DICTRA simulation shows that existence of second phase could introduce microstructure effect on diffusion. This microstructure effect may be taken into account for promoting or blocking the diffusion.
Dynamics of atom-field probability amplitudes in a coupled cavity system with Kerr non-linearity
Priyesh, K. V.; Thayyullathil, Ramesh Babu
2014-01-28
We have investigated the dynamics of two cavities coupled together via photon hopping, filled with Kerr non-linear medium and each containing a two level atom in it. The evolution of various atom (field) state probabilities of the coupled cavity system in two excitation sub space are obtained numerically. Detailed analysis has been done by taking different initial conditions of the system, with various coupling strengths and by varying the susceptibility of the medium. The role of susceptibility factor, on the dynamics atom field probability has been examined. In a coupled cavity system with strong photon hopping it is found that the susceptibility factor modifies the behaviour of probability amplitudes.
NASA Astrophysics Data System (ADS)
Hatheway, Alson E.
2015-09-01
A common mechanical failure in optical systems is inadequate stability in the supporting structure. Thermal stability is crucial for maintaining the alignment of the optical elements and achieving adequate optical performance as the environmental temperature changes. It is the responsibility of the mechanical engineer to provide adequate stability in the mechanical design. Optical engineers assume that their large-displacement non-linear codes are required to analyze the perturbations caused by mechanical deflections. However, the permitted deflections of the optical elements are usually quite small, on the order of microns for structures of meter-sized dimensions. For perturbations of this magnitude it may be shown that a non-linear solver is not required for engineering accuracies. In fact, it can be argued that the optical functions are more linear than the solid mechanics functions, of which the finite element method itself is but a linear simplification. Unified optomechanical modeling provides a vehicle for tracing offending image motions to particular optical elements and their supporting structure. The unified modeling method imports the optical elements' imaging properties into a finite element structural model of the optical system. It convolves the elements' motions and their optical properties in a single optomechanical modeling medium, unifying them. This provides the engineer with a tool that discloses each element's contribution to the offending motions of the image on the detector. This paper presents the theory of unified optomechanical modeling as applied to the thermal stability of the optical image in a Nastran1 finite element model. The steps used in developing a unified optomechanical model are described in detail. Comparisons of the unified modeling technique to both analytical and empirical validation studies are shown.
Unified optomechanical modeling: stabilizing the line-of-sight of an IR imager
NASA Astrophysics Data System (ADS)
Hatheway, Alson E.
2015-09-01
A common mechanical failure in optical systems is inadequate stiffness in the supporting structure. Stiffness is crucial for maintaining the alignment of the optical elements and achieving adequate optical performance. It is the responsibility of the mechanical engineer to provide adequate stiffness in the mechanical design. Optical engineers assume that their large-displacement non-linear codes are required to analyze the perturbations caused by mechanical deflections. However, the permitted deflections of the optical elements are usually quite small, on the order of microns for structures of meter-sized dimensions. For perturbations of this magnitude it may be shown that a non-linear solver is not required for engineering accuracies. In fact, it can be argued that the optical functions are more linear than the solid mechanics functions, of which the finite element method itself is but a linear simplification. Unified optomechanical modeling provides a vehicle for tracing offending image motions to particular optical elements and their supporting structure. The unified modeling method imports the optical elements' imaging properties into a finite element structural model of the optical system. It convolves the elements' motions and their optical properties in a single optomechanical modeling medium, unifying them. This provides the engineer with a tool that discloses each element's contribution to the offending motions of the image on the detector. This paper presents the theory of unified optomechanical modeling as applied to the optical line-of-sight in a Nastran1 finite element model. The steps used in developing a unified optomechanical model are described in detail. Comparisons of the unified modeling technique to both analytical and empirical validation studies are shown.
Wave excitation by nonlinear coupling among shear Alfvén waves in a mirror-confined plasma
Ikezoe, R. Ichimura, M.; Okada, T.; Hirata, M.; Yokoyama, T.; Iwamoto, Y.; Sumida, S.; Jang, S.; Takeyama, K.; Yoshikawa, M.; Kohagura, J.; Shima, Y.; Wang, X.
2015-09-15
A shear Alfvén wave at slightly below the ion-cyclotron frequency overcomes the ion-cyclotron damping and grows because of the strong anisotropy of the ion temperature in the magnetic mirror configuration, and is called the Alfvén ion-cyclotron (AIC) wave. Density fluctuations caused by the AIC waves and the ion-cyclotron range of frequencies (ICRF) waves used for ion heating have been detected using a reflectometer in a wide radial region of the GAMMA 10 tandem mirror plasma. Various wave-wave couplings are clearly observed in the density fluctuations in the interior of the plasma, but these couplings are not so clear in the magnetic fluctuations at the plasma edge when measured using a pick-up coil. A radial dependence of the nonlinearity is found, particularly in waves with the difference frequencies of the AIC waves; bispectral analysis shows that such wave-wave coupling is significant near the core, but is not so evident at the periphery. In contrast, nonlinear coupling with the low-frequency background turbulence is quite distinct at the periphery. Nonlinear coupling associated with the AIC waves may play a significant role in the beta- and anisotropy-limits of a mirror-confined plasma through decay of the ICRF heating power and degradation of the plasma confinement by nonlinearly generated waves.
Beninato, A.; Baglio, S.; Andò, B.; Emery, T.; Bulsara, A. R.; Jenkins, C.; Palkar, V.
2013-12-09
Multiferroic (MF) composites, in which magnetic and ferroelectric orders coexist, represent a very attractive class of materials with promising applications in areas, such as spintronics, memories, and sensors. One of the most important multiferroics is the perovskite phase of bismuth ferrite, which exhibits weak magnetoelectric properties at room temperature; its properties can be enhanced by doping with other elements such as dysprosium. A recent paper has demonstrated that a thin film of Bi{sub 0.7}Dy{sub 0.3}FeO{sub 3} shows good magnetoelectric coupling. In separate work it has been shown that a carefully crafted ring connection of N (N odd and N ≥ 3) ferroelectric capacitors yields, past a critical point, nonlinear oscillations that can be exploited for electric (E) field sensing. These two results represent the starting point of our work. In this paper the (electrical) hysteresis, experimentally measured in the MF material Bi{sub 0.7}Dy{sub 0.3}FeO{sub 3}, is characterized with the applied magnetic field (B) taken as a control parameter. This yields a “blueprint” for a magnetic (B) field sensor: a ring-oscillator coupling of N = 3 Sawyer-Tower circuits each underpinned by a mutliferroic element. In this configuration, the changes induced in the ferroelectric behavior by the external or “target” B-field are quantified, thus providing a pathway for very low power and high sensitivity B-field sensing.
NASA Astrophysics Data System (ADS)
Beninato, A.; Emery, T.; Baglio, S.; Andò, B.; Bulsara, A. R.; Jenkins, C.; Palkar, V.
2013-12-01
Multiferroic (MF) composites, in which magnetic and ferroelectric orders coexist, represent a very attractive class of materials with promising applications in areas, such as spintronics, memories, and sensors. One of the most important multiferroics is the perovskite phase of bismuth ferrite, which exhibits weak magnetoelectric properties at room temperature; its properties can be enhanced by doping with other elements such as dysprosium. A recent paper has demonstrated that a thin film of Bi0.7Dy0.3FeO3 shows good magnetoelectric coupling. In separate work it has been shown that a carefully crafted ring connection of N (N odd and N ≥ 3) ferroelectric capacitors yields, past a critical point, nonlinear oscillations that can be exploited for electric (E) field sensing. These two results represent the starting point of our work. In this paper the (electrical) hysteresis, experimentally measured in the MF material Bi0.7Dy0.3FeO3, is characterized with the applied magnetic field (B) taken as a control parameter. This yields a "blueprint" for a magnetic (B) field sensor: a ring-oscillator coupling of N = 3 Sawyer-Tower circuits each underpinned by a mutliferroic element. In this configuration, the changes induced in the ferroelectric behavior by the external or "target" B-field are quantified, thus providing a pathway for very low power and high sensitivity B-field sensing.
NASA Astrophysics Data System (ADS)
Liu, Shuang; Zhao, Shuang-Shuang; Wang, Zhao-Long; Li, Hai-Bin
2015-01-01
The stability and the Hopf bifurcation of a nonlinear electromechanical coupling system with time delay feedback are studied. By considering the energy in the air-gap field of the AC motor, the dynamical equation of the electromechanical coupling transmission system is deduced and a time delay feedback is introduced to control the dynamic behaviors of the system. The characteristic roots and the stable regions of time delay are determined by the direct method, and the relationship between the feedback gain and the length summation of stable regions is analyzed. Choosing the time delay as a bifurcation parameter, we find that the Hopf bifurcation occurs when the time delay passes through a critical value. A formula for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions is given by using the normal form method and the center manifold theorem. Numerical simulations are also performed, which confirm the analytical results. Project supported by the National Natural Science Foundation of China (Grant No. 61104040), the Natural Science Foundation of Hebei Province, China (Grant No. E2012203090), and the University Innovation Team of Hebei Province Leading Talent Cultivation Project, China (Grant No. LJRC013).
Lee, Shiu-Hang; Nagataki, Shigehiro; Ellison, Donald C. E-mail: nagataki@yukawa.kyoto-u.ac.jp
2012-05-10
To better model the efficient production of cosmic rays (CRs) in supernova remnants (SNRs) with the associated coupling between CR production and SNR dynamics, we have generalized an existing cr-hydro-NEI code to include the following processes: (1) an explicit calculation of the upstream precursor structure including the position-dependent flow speed, density, temperature, and magnetic field strength; (2) a momentum- and space-dependent CR diffusion coefficient; (3) an explicit calculation of magnetic field amplification; (4) calculation of the maximum CR momentum using the amplified magnetic field; (5) a finite Alfven speed for the particle scattering centers; and (6) the ability to accelerate a superthermal seed population of CRs, as well as the ambient thermal plasma. While a great deal of work has been done modeling SNRs, most work has concentrated on either the continuum emission from relativistic electrons or ions or the thermal emission from the shock heated plasma. Our generalized code combines these elements and describes the interplay between CR production and SNR evolution, including the nonlinear coupling of efficient diffusive shock acceleration, based mainly on the work of P. Blasi and coworkers, and a non-equilibrium ionization (NEI) calculation of thermal X-ray line emission. We believe that our generalized model will provide a consistent modeling platform for SNRs, including those interacting with molecular clouds, and improve the interpretation of current and future observations, including the high-quality spectra expected from Astro-H. SNR RX J1713.7-3946 is modeled as an example.
Testing universal relations of neutron stars with a nonlinear matter-gravity coupling theory
Sham, Y.-H.; Lin, L.-M.; Leung, P. T. E-mail: lmlin@phy.cuhk.edu.hk
2014-02-01
Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different physical quantities of NSs can exist. Lau et al. found that the frequency of the f-mode oscillation, the mass, and the moment of inertia are connected by universal relations. More recently, Yagi and Yunes discovered the I-Love-Q universal relations among the mass, the moment of inertia, the Love number, and the quadrupole moment. In this paper, we study these universal relations in the Eddington-inspired Born-Infeld (EiBI) gravity. This theory differs from general relativity (GR) significantly only at high densities due to the nonlinear coupling between matter and gravity. It thus provides us an ideal case to test how robust the universal relations of NSs are with respect to the change of the gravity theory. Due to the apparent EOS formulation of EiBI gravity developed recently by Delsate and Steinhoff, we are able to study the universal relations in EiBI gravity using the same techniques as those in GR. We find that the universal relations in EiBI gravity are essentially the same as those in GR. Our work shows that, within the currently viable coupling constant, there exists at least one modified gravity theory that is indistinguishable from GR in view of the unexpected universal relations.
Partial synchronization in networks of non-linearly coupled oscillators: The Deserter Hubs Model
NASA Astrophysics Data System (ADS)
Freitas, Celso; Macau, Elbert; Pikovsky, Arkady
2015-04-01
We study the Deserter Hubs Model: a Kuramoto-like model of coupled identical phase oscillators on a network, where attractive and repulsive couplings are balanced dynamically due to nonlinearity of interactions. Under weak force, an oscillator tends to follow the phase of its neighbors, but if an oscillator is compelled to follow its peers by a sufficient large number of cohesive neighbors, then it actually starts to act in the opposite manner, i.e., in anti-phase with the majority. Analytic results yield that if the repulsion parameter is small enough in comparison with the degree of the maximum hub, then the full synchronization state is locally stable. Numerical experiments are performed to explore the model beyond this threshold, where the overall cohesion is lost. We report in detail partially synchronous dynamical regimes, like stationary phase-locking, multistability, periodic and chaotic states. Via statistical analysis of different network organizations like tree, scale-free, and random ones, we found a measure allowing one to predict relative abundance of partially synchronous stationary states in comparison to time-dependent ones.
NASA Astrophysics Data System (ADS)
Rury, Aaron S.
2016-06-01
This study reports experimental, computational, and theoretical evidence for a previously unobserved coherent phonon-phonon interaction in an organic solid that can be described by the application of Fano's analysis to a case without the presence of a continuum. Using Raman spectroscopy of the hydrogen-bonded charge-transfer material quinhydrone, two peaks appear near 700 cm-1 we assign as phonons whose position and line-shape asymmetry depend on the sample temperature and light scattering excitation energy. Density functional theory calculations find two nearly degenerate phonons possessing frequencies near the values found in experiment that share similar atomic motion out of the aromatic plane of electron donor and acceptor molecules of quinhydrone. Further analytical modeling of the steady-state light scattering process using the Peierls-Hubbard Hamiltonian and time-dependent perturbation theory motivates assignment of the physical origin of the asymmetric features of each peak's line shape to an interaction between two discrete phonons via nonlinear electron-phonon coupling. In the context of analytical model results, characteristics of the experimental spectra upon 2.33 eV excitation of the Raman scattering process are used to qualify the temperature dependence of the magnitude of this coupling in the valence band of quinhydrone. These results broaden the range of phonon-phonon interactions in materials in general while also highlighting the rich physics and fundamental attributes specific to organic solids that may determine their applicability in next generation electronics and photonics technologies.
Discrete breathers for a discrete nonlinear Schrödinger ring coupled to a central site.
Jason, Peter; Johansson, Magnus
2016-01-01
We examine the existence and properties of certain discrete breathers for a discrete nonlinear Schrödinger model where all but one site are placed in a ring and coupled to the additional central site. The discrete breathers we focus on are stationary solutions mainly localized on one or a few of the ring sites and possibly also the central site. By numerical methods, we trace out and study the continuous families the discrete breathers belong to. Our main result is the discovery of a split bifurcation at a critical value of the coupling between neighboring ring sites. Below this critical value, families form closed loops in a certain parameter space, implying that discrete breathers with and without central-site occupation belong to the same family. Above the split bifurcation the families split up into several separate ones, which bifurcate with solutions with constant ring amplitudes. For symmetry reasons, the families have different properties below the split bifurcation for even and odd numbers of sites. It is also determined under which conditions the discrete breathers are linearly stable. The dynamics of some simpler initial conditions that approximate the discrete breathers are also studied and the parameter regimes where the dynamics remain localized close to the initially excited ring site are related to the linear stability of the exact discrete breathers. PMID:26871085
Parameter estimation in a structural acoustic system with fully nonlinear coupling conditions
NASA Technical Reports Server (NTRS)
Banks, H. T.; Smith, Ralph C.
1994-01-01
A methodology for estimating physical parameters in a class of structural acoustic systems is presented. The general model under consideration consists of an interior cavity which is separated from an exterior noise source by an enclosing elastic structure. Piezoceramic patches are bonded to or embedded in the structure; these can be used both as actuators and sensors in applications ranging from the control of interior noise levels to the determination of structural flaws through nondestructive evaluation techniques. The presence and excitation of patches, however, changes the geometry and material properties of the structure as well as involves unknown patch parameters, thus necessitating the development of parameter estimation techniques which are applicable in this coupled setting. In developing a framework for approximation, parameter estimation and implementation, strong consideration is given to the fact that the input operator is unbonded due to the discrete nature of the patches. Moreover, the model is weakly nonlinear. As a result of the coupling mechanism between the structural vibrations and the interior acoustic dynamics. Within this context, an illustrating model is given, well-posedness and approximations results are discussed and an applicable parameter estimation methodology is presented. The scheme is then illustrated through several numerical examples with simulations modeling a variety of commonly used structural acoustic techniques for systems excitations and data collection.
Partial synchronization in networks of non-linearly coupled oscillators: The Deserter Hubs Model
Freitas, Celso Macau, Elbert; Pikovsky, Arkady
2015-04-15
We study the Deserter Hubs Model: a Kuramoto-like model of coupled identical phase oscillators on a network, where attractive and repulsive couplings are balanced dynamically due to nonlinearity of interactions. Under weak force, an oscillator tends to follow the phase of its neighbors, but if an oscillator is compelled to follow its peers by a sufficient large number of cohesive neighbors, then it actually starts to act in the opposite manner, i.e., in anti-phase with the majority. Analytic results yield that if the repulsion parameter is small enough in comparison with the degree of the maximum hub, then the full synchronization state is locally stable. Numerical experiments are performed to explore the model beyond this threshold, where the overall cohesion is lost. We report in detail partially synchronous dynamical regimes, like stationary phase-locking, multistability, periodic and chaotic states. Via statistical analysis of different network organizations like tree, scale-free, and random ones, we found a measure allowing one to predict relative abundance of partially synchronous stationary states in comparison to time-dependent ones.
NASA Astrophysics Data System (ADS)
Emenheiser, Jeffrey; Chapman, Airlie; Pósfai, Márton; Crutchfield, James P.; Mesbahi, Mehran; D'Souza, Raissa M.
2016-09-01
Following the long-lived qualitative-dynamics tradition of explaining behavior in complex systems via the architecture of their attractors and basins, we investigate the patterns of switching between distinct trajectories in a network of synchronized oscillators. Our system, consisting of nonlinear amplitude-phase oscillators arranged in a ring topology with reactive nearest-neighbor coupling, is simple and connects directly to experimental realizations. We seek to understand how the multiple stable synchronized states connect to each other in state space by applying Gaussian white noise to each of the oscillators' phases. To do this, we first analytically identify a set of locally stable limit cycles at any given coupling strength. For each of these attracting states, we analyze the effect of weak noise via the covariance matrix of deviations around those attractors. We then explore the noise-induced attractor switching behavior via numerical investigations. For a ring of three oscillators, we find that an attractor-switching event is always accompanied by the crossing of two adjacent oscillators' phases. For larger numbers of oscillators, we find that the distribution of times required to stochastically leave a given state falls off exponentially, and we build an attractor switching network out of the destination states as a coarse-grained description of the high-dimensional attractor-basin architecture.
Nonlinear Brillouin amplification of finite-duration seeds in the strong coupling regime
Lehmann, G.; Spatschek, K. H.
2013-07-15
Parametric plasma processes received renewed interest in the context of generating ultra-intense and ultra-short laser pulses up to the exawatt-zetawatt regime. Both Raman as well as Brillouin amplifications of seed pulses were proposed. Here, we investigate Brillouin processes in the one-dimensional (1D) backscattering geometry with the help of numerical simulations. For optimal seed amplification, Brillouin scattering is considered in the so called strong coupling (sc) regime. Special emphasis lies on the dependence of the amplification process on the finite duration of the initial seed pulses. First, the standard plane-wave instability predictions are generalized to pulse models, and the changes of initial seed pulse forms due to parametric instabilities are investigated. Three-wave-interaction results are compared to predictions by a new (kinetic) Vlasov code. The calculations are then extended to the nonlinear region with pump depletion. Generation of different seed layers is interpreted by self-similar solutions of the three-wave interaction model. Similar to Raman amplification, shadowing of the rear layers by the leading layers of the seed occurs. The shadowing is more pronounced for initially broad seed pulses. The effect is quantified for Brillouin amplification. Kinetic Vlasov simulations agree with the three-wave interaction predictions and thereby affirm the universal validity of self-similar layer formation during Brillouin seed amplification in the strong coupling regime.
All-Optical Optomechanics: An Optical Spring Mirror
NASA Astrophysics Data System (ADS)
Singh, Swati; Phelps, Gregory; Goldbaum, Dan; Wright, Ewan; Meystre, Pierre
2011-05-01
The dominant hurdle to the operation of optomechanical systems in the quantum regime is the coupling of the vibrating element to a thermal reservoir via mechanical supports. Here we propose a scheme that uses an optical spring to replace the mechanical support. We show that the resolved-sideband regime of cooling can be reached in a configuration using a high-reflectivity disk mirror held by an optical tweezer as one of the end mirrors of a Fabry-Perot cavity. We find a final phonon occupation number of the trapped mirror n = 0.56 for reasonable parameters, the limit being set by our approximations, and not any fundamental physics. This demonstrates the promise of dielectric disks attached to optical springs for the observation of quantum effects in macroscopic objects. This work was supported by the US Office of Naval Research, the US National Science Foundation, the US Army Research Office and the DARPA ORCHID program through a grant from AFOSR.
Quantum synchronization in an optomechanical system based on Lyapunov control
NASA Astrophysics Data System (ADS)
Li, Wenlin; Li, Chong; Song, Heshan
2016-06-01
We extend the concepts of quantum complete synchronization and phase synchronization, which were proposed in A. Mari et al., Phys. Rev. Lett. 111, 103605 (2013), 10.1103/PhysRevLett.111.103605, to more widespread quantum generalized synchronization. Generalized synchronization can be considered a necessary condition or a more flexible derivative of complete synchronization, and its criterion and synchronization measure are proposed and analyzed in this paper. As examples, we consider two typical generalized synchronizations in a designed optomechanical system. Unlike the effort to construct a special coupling synchronization system, we purposefully design extra control fields based on Lyapunov control theory. We find that the Lyapunov function can adapt to more flexible control objectives, which is more suitable for generalized synchronization control, and the control fields can be achieved simply with a time-variant voltage. Finally, the existence of quantum entanglement in different generalized synchronizations is also discussed.
Slowing and stopping light with an optomechanical crystal array
Chang, D. E.; Safavi-Naeini, A. H.; Painter, O.; Hafezi, M.
2010-10-07
The ability to coherently store and retrieve optical information in a rapidly tunable manner is an important ingredient for all-optical information processing. In the classical domain, this optical buffering is necessary to manage information flow in complex networks. In quantum information processing, such a system can also serve as a long-term memory capable of storing the full quantum information contained in an optical pulse. Here we suggest a novel approach to light storage involving an optical waveguide coupled to an optomechanical crystal array, where light in the waveguide can be dynamically and reversibly mapped into long-lived mechanical vibrations in the array. This technique enables large bandwidths and long storage and delay times in a compact, on-chip platform.
Non-linear resonant coupling of tsunami edge waves using stochastic earthquake source models
Geist, Eric L.
2015-01-01
Non-linear resonant coupling of edge waves can occur with tsunamis generated by large-magnitude subduction zone earthquakes. Earthquake rupture zones that straddle beneath the coastline of continental margins are particularly efficient at generating tsunami edge waves. Using a stochastic model for earthquake slip, it is shown that a wide range of edge-wave modes and wavenumbers can be excited, depending on the variability of slip. If two modes are present that satisfy resonance conditions, then a third mode can gradually increase in amplitude over time, even if the earthquake did not originally excite that edge-wave mode. These three edge waves form a resonant triad that can cause unexpected variations in tsunami amplitude long after the first arrival. An M ∼ 9, 1100 km-long continental subduction zone earthquake is considered as a test case. For the least-variable slip examined involving a Gaussian random variable, the dominant resonant triad includes a high-amplitude fundamental mode wave with wavenumber associated with the along-strike dimension of rupture. The two other waves that make up this triad include subharmonic waves, one of fundamental mode and the other of mode 2 or 3. For the most variable slip examined involving a Cauchy-distributed random variable, the dominant triads involve higher wavenumbers and modes because subevents, rather than the overall rupture dimension, control the excitation of edge waves. Calculation of the resonant period for energy transfer determines which cases resonant coupling may be instrumentally observed. For low-mode triads, the maximum transfer of energy occurs approximately 20–30 wave periods after the first arrival and thus may be observed prior to the tsunami coda being completely attenuated. Therefore, under certain circumstances the necessary ingredients for resonant coupling of tsunami edge waves exist, indicating that resonant triads may be observable and implicated in late, large-amplitude tsunami arrivals.
Non-linear resonant coupling of tsunami edge waves using stochastic earthquake source models
NASA Astrophysics Data System (ADS)
Geist, Eric L.
2016-02-01
Non-linear resonant coupling of edge waves can occur with tsunamis generated by large-magnitude subduction zone earthquakes. Earthquake rupture zones that straddle beneath the coastline of continental margins are particularly efficient at generating tsunami edge waves. Using a stochastic model for earthquake slip, it is shown that a wide range of edge-wave modes and wavenumbers can be excited, depending on the variability of slip. If two modes are present that satisfy resonance conditions, then a third mode can gradually increase in amplitude over time, even if the earthquake did not originally excite that edge-wave mode. These three edge waves form a resonant triad that can cause unexpected variations in tsunami amplitude long after the first arrival. An M ˜ 9, 1100 km-long continental subduction zone earthquake is considered as a test case. For the least-variable slip examined involving a Gaussian random variable, the dominant resonant triad includes a high-amplitude fundamental mode wave with wavenumber associated with the along-strike dimension of rupture. The two other waves that make up this triad include subharmonic waves, one of fundamental mode and the other of mode 2 or 3. For the most variable slip examined involving a Cauchy-distributed random variable, the dominant triads involve higher wavenumbers and modes because subevents, rather than the overall rupture dimension, control the excitation of edge waves. Calculation of the resonant period for energy transfer determines which cases resonant coupling may be instrumentally observed. For low-mode triads, the maximum transfer of energy occurs approximately 20-30 wave periods after the first arrival and thus may be observed prior to the tsunami coda being completely attenuated. Therefore, under certain circumstances the necessary ingredients for resonant coupling of tsunami edge waves exist, indicating that resonant triads may be observable and implicated in late, large-amplitude tsunami arrivals.
Low loss optomechanical cavities based on silicon oscillator
NASA Astrophysics Data System (ADS)
Borrielli, A.; Pontin, A.; Cataliotti, F. S.; Marconi, L.; Marin, F.; Marino, F.; Pandraud, G.; Prodi, G. A.; Serra, E.; Bonaldi, M.
2015-05-01
In an optomechanical cavity the optical and mechanical degree of freedom are strongly coupled by the radiation pressure of the light. This field of research has been gathering a lot of momentum during the last couple of years, driven by the technological advances in microfabrication and the first observation of quantum phenomena. These results open new perspectives in a wide range of applications, including high sensitivity measurements of position, acceleration, force, mass, and for fundamental research. We are working on low frequency pondero-motive light squeezing as a tool for improving the sensitivity of audio frequency measuring devices such as magnetic resonance force microscopes and gravitational-wave detectors. It is well known that experiments aiming to produce and manipulate non-classical (squeezed) light by effect of optomechanical interaction need a mechanical oscillator with low optical and mechanical losses. These technological requirements permit to maximize the force per incoming photon exerted by the cavity field on the mechanical element and to improve the element's response to the radiation pressure force and, at the same time, to decrease the influence of the thermal bath. In this contribution we describe a class of mechanical devices for which we measured a mechanical quality factor up to 1.2 × 106 and with which it was possible to build a Fabry-Perot cavity with optical finesse up to 9 × 104. From our estimations, these characteristics meet the requirements for the generation of radiation squeezing and quantum correlations in the ˜ 100kHz region. Moreover our devices are characterized by high reproducibility to allow inclusion in integrated systems. We show the results of the characterization realized with a Michelson interferometer down to 4.2K and measurements in optical cavities performed at cryogenic temperature with input optical powers up to a few mW. We also report on the dynamical stability and the thermal response of the system.
Nonlinear dynamics of optical absorption of intense beams
NASA Astrophysics Data System (ADS)
Corbett, D.; van Oosten, C. L.; Warner, M.
2008-07-01
On traversing materials with absorbing dyes, weak optical beams decay exponentially (a Beer profile), while intense beams develop in time a profile that is spatially linear until at great depth it becomes spatially exponential. This anomalous, deep penetration, due to photobleaching of surface layers, is important for heavy dye loading and intense beams, for instance in photo-actuation. We address the problem of the evolution in time from initial Beer’s Law to a finally deeply-penetrating optical profile in dyes. Our largely analytic solution of the coupled, nonlinear, partial differential equations governing the spatiotemporal decay of the Poynting flux and the nonlinear population dynamics of the photo-active molecules under intense irradiation has application to optomechanical devices.
Dynamics and transmissivity of optomechanical system in squeezed environment
NASA Astrophysics Data System (ADS)
Farooq, K.; Khan, M. A.; Wang, L. C.; Yi, X. X.
2015-10-01
Cavity quantum optomechanics offers the potential to explore quantum nature and characteristics in microscopic and nanoquantum systems. In this area, various experimental setup trends to explore, while theoretical approaches seek to lead the concrete bases for these amazing characteristics. In this paper, we present the dynamic features, stabilization and the optical response (transmission) properties of an optomechanical system in the squeezed environment theoretically. Particularly, we calculate optical intensity transmission coefficient of the optomechanical system. The optomechanical system has driven coherently with the external laser field.
NASA Astrophysics Data System (ADS)
Le, Thai-Hoa; Caracoglia, Luca
2015-05-01
A tall building is prone to wind-induced stochastic vibration, originating from complex fluid-structure interaction, dynamic coupling and nonlinear aerodynamic phenomena. The loading induced by extreme wind events, such as "downburst storms", hurricanes and tornadoes is naturally transient and nonstationary in comparison with the hypothesis of stationary wind loads, used in both structural engineering research and practice. Time-domain integration methods, widely applied for solving nonlinear differential equations, are hardly applicable to the analysis of coupled, nonlinear and stochastic response of tall buildings under transient winds. Therefore, the investigation of alternative and computationally-efficient simulation methods is important. This study employs the wavelet-Galerkin (WG) method to achieve this objective, by examining the stochastic dynamic response of two tall building models subject to stationary and transient wind loads. These are (1) a single-degree-of-freedom equivalent model of a tall structure and (2) a multi-degree-of-freedom reduced-order full building model. Compactly supported Daubechies wavelets are used as orthonormal basis functions in conjunction with the Galerkin projection scheme to decompose and transform the coupled, nonlinear differential equations of the two models into random algebraic equations in the wavelet domain. Methodology, feasibility and applicability of the WG method are investigated in some special cases of stiffness nonlinearity (Duffing type) and damping nonlinearity (Van-der-Pol type) for the single-degree-of-freedom model. For the reduced-order tall building model the WG method is used to solve for dynamic coupling, aerodynamics and transient wind load effects. Computation of "connection coefficients", effects of boundary conditions, wavelet resolution and wavelet order are examined in order to adequately replicate the dynamic response. Realizations of multivariate stationary and transient wind loads for the
Implicit time-integration method for simultaneous solution of a coupled non-linear system
NASA Astrophysics Data System (ADS)
Watson, Justin Kyle
. The thesis also outlines the basic concepts behind the nodal balance equations, heat transfer equations and the thermal hydraulic equations, which will be coupled to form a fully implicit nonlinear system of equations. The coupling of separate physics models to solve a larger problem and improve accuracy and efficiency of a calculation is not a new idea, however implementing them in an implicit manner and solving the system simultaneously is. Also the application to reactor safety codes is new and has not be done with thermal hydraulics and neutronics codes on realistic applications in the past. The coupling technique described in this thesis is applicable to other similar coupled thermal hydraulic and core physics reactor safety codes. This technique is demonstrated using coupled input decks to show that the system is solved correctly and then verified by using two derivative test problems based on international benchmark problems the OECD/NRC Three mile Island (TMI) Main Steam Line Break (MSLB) problem (representative of pressurized water reactor analysis) and the OECD/NRC Peach Bottom (PB) Turbine Trip (TT) benchmark (representative of boiling water reactor analysis).
Interpreting the nonlinear dielectric response of glass-formers in terms of the coupling model
Ngai, K. L.
2015-03-21
Nonlinear dielectric measurements at high electric fields of glass-forming glycerol and propylene carbonate initially were carried out to elucidate the dynamic heterogeneous nature of the structural α-relaxation. Recently, the measurements were extended to sufficiently high frequencies to investigate the nonlinear dielectric response of faster processes including the so-called excess wing (EW), appearing as a second power law at high frequencies in the loss spectra of many glass formers without a resolved secondary relaxation. While a strong increase of dielectric constant and loss is found in the nonlinear dielectric response of the α-relaxation, there is a lack of significant change in the EW. A surprise to the experimentalists finding it, this difference in the nonlinear dielectric properties between the EW and the α-relaxation is explained in the framework of the coupling model by identifying the EW investigated with the nearly constant loss (NCL) of caged molecules, originating from the anharmonicity of the intermolecular potential. The NCL is terminated at longer times (lower frequencies) by the onset of the primitive relaxation, which is followed sequentially by relaxation processes involving increasing number of molecules until the terminal Kohlrausch α-relaxation is reached. These intermediate faster relaxations, combined to form the so-called Johari-Goldstein (JG) β-relaxation, are spatially and dynamically heterogeneous, and hence exhibit nonlinear dielectric effects, as found in glycerol and propylene carbonate, where the JG β-relaxation is not resolved and in D-sorbitol where it is resolved. Like the linear susceptibility, χ{sub 1}(f), the frequency dispersion of the third-order dielectric susceptibility, χ{sub 3}(f), was found to depend primarily on the α-relaxation time, and independent of temperature T and pressure P. I show this property of the frequency dispersions of χ{sub 1}(f) and χ{sub 3}(f) is the characteristic of the many
Macroscopic Quantum Superposition in Cavity Optomechanics
NASA Astrophysics Data System (ADS)
Liao, Jie-Qiao; Tian, Lin
Quantum superposition in mechanical systems is not only a key evidence of macroscopic quantum coherence, but can also be utilized in modern quantum technology. Here we propose an efficient approach for creating macroscopically distinct mechanical superposition states in a two-mode optomechanical system. Photon hopping between the two cavity-modes is modulated sinusoidally. The modulated photon tunneling enables an ultrastrong radiation-pressure force acting on the mechanical resonator, and hence significantly increases the mechanical displacement induced by a single photon. We present systematic studies on the generation of the Yurke-Stoler-like states in the presence of system dissipations. The state generation method is general and it can be implemented with either optomechanical or electromechanical systems. The authors are supported by the National Science Foundation under Award No. NSF-DMR-0956064 and the DARPA ORCHID program through AFOSR.
NASA Astrophysics Data System (ADS)
Zhang, J.; Gao, Q.; Tan, S. J.; Zhong, W. X.
2012-10-01
A new method is proposed as a solution for the large-scale coupled vehicle-track dynamic model with nonlinear wheel-rail contact. The vehicle is simplified as a multi-rigid-body model, and the track is treated as a three-layer beam model. In the track model, the rail is assumed to be an Euler-Bernoulli beam supported by discrete sleepers. The vehicle model and the track model are coupled using Hertzian nonlinear contact theory, and the contact forces of the vehicle subsystem and the track subsystem are approximated by the Lagrange interpolation polynomial. The response of the large-scale coupled vehicle-track model is calculated using the precise integration method. A more efficient algorithm based on the periodic property of the track is applied to calculate the exponential matrix and certain matrices related to the solution of the track subsystem. Numerical examples demonstrate the computational accuracy and efficiency of the proposed method.
Optomechanical shape analysis using group theory.
Magnes, Jenny; Kinneberg, Margo; Khakurel, Rahul; Melikechi, Noureddine
2010-08-01
We describe an optomechanical technique using a knife-edge, which is scanned spatially across a beam of light to identify shape-based irradiance. Symmetry groups are identified through linear and rotational scanning signatures of illuminated shapes. The scanning signature is used to classify the shape into a symmetry group. To demonstrate the shape analysis technique, we have classified basic geometric shapes, which belong to the orthogonal and dihedral symmetry groups O(2), D(2), D(3), and D(6). PMID:20676172
High-frequency and high-quality silicon carbide optomechanical microresonators
Lu, Xiyuan; Lee, Jonathan Y.; Lin, Qiang
2015-01-01
Silicon carbide (SiC) exhibits excellent material properties attractive for broad applications. We demonstrate the first SiC optomechanical microresonators that integrate high mechanical frequency, high mechanical quality, and high optical quality into a single device. The radial-breathing mechanical mode has a mechanical frequency up to 1.69 GHz with a mechanical Q around 5500 in atmosphere, which corresponds to a fm · Qm product as high as 9.47 × 1012 Hz. The strong optomechanical coupling allows us to efficiently excite and probe the coherent mechanical oscillation by optical waves. The demonstrated devices, in combination with the superior thermal property, chemical inertness, and defect characteristics of SiC, show great potential for applications in metrology, sensing, and quantum photonics, particularly in harsh environments that are challenging for other device platforms. PMID:26585637
High-frequency and high-quality silicon carbide optomechanical microresonators.
Lu, Xiyuan; Lee, Jonathan Y; Lin, Qiang
2015-01-01
Silicon carbide (SiC) exhibits excellent material properties attractive for broad applications. We demonstrate the first SiC optomechanical microresonators that integrate high mechanical frequency, high mechanical quality, and high optical quality into a single device. The radial-breathing mechanical mode has a mechanical frequency up to 1.69 GHz with a mechanical Q around 5500 in atmosphere, which corresponds to a fm · Qm product as high as 9.47 × 10(12) Hz. The strong optomechanical coupling allows us to efficiently excite and probe the coherent mechanical oscillation by optical waves. The demonstrated devices, in combination with the superior thermal property, chemical inertness, and defect characteristics of SiC, show great potential for applications in metrology, sensing, and quantum photonics, particularly in harsh environments that are challenging for other device platforms. PMID:26585637
Dynamical back-action at 5.5 GHz in a corrugated optomechanical beam
Navarro-Urrios, D.; Gomis-Bresco, J.; Alzina, F.; El-Jallal, S.; Oudich, M.; Pennec, Y.; Djafari-Rouhani, B.; Pitanti, A.; Capuj, N.; Tredicucci, A.; Griol, A.; Martínez, A.; Sotomayor Torres, C. M.
2014-12-15
We report on the optomechanical properties of a breathing mechanical mode oscillating at 5.5 GHz in a 1D corrugated Si nanobeam. This mode has an experimental single-particle optomechanical coupling rate of |g{sub o,OM}| = 1.8 MHz (|g{sub o,OM}|/2π = 0.3 MHz) and shows strong dynamical back-action effects at room temperature. The geometrical flexibility of the unit-cell would lend itself to further engineering of the cavity region to localize the mode within the full phononic band-gap present at 4 GHz while keeping high g{sub o,OM} values. This would lead to longer lifetimes at cryogenic temperatures, due to the suppression of acoustic leakage.
Single-photon scattering in an optomechanical Jaynes-Cummings model
NASA Astrophysics Data System (ADS)
Ng, K. H.; Law, C. K.
2016-04-01
We investigate an optomechanical system which realizes the Jaynes-Cummings (JC) model known in cavity QED. Such a system consists of a single photon and an optomechanical cavity with two optical cavity modes and one mechanical mode. Under the resonance condition when the mechanical frequency is close to the frequency difference between the optical modes, the photon and phonons can be strongly coupled. We present an analytic solution of single-photon scattering and show that the spectrum of the scattered photon exhibits excitation-number-dependent Rabi splitting of the JC model. In addition, we examine the response of the mechanical mode to a sequence of single photons, with one photon in the cavity at a time. We show that sequential photon scattering can efficiently excite the mechanical mode and generate sub-Poisson phonon statistics.
Quantum optics, cavity QED, and quantum optomechanics
NASA Astrophysics Data System (ADS)
Meystre, Pierre
2013-05-01
Quantum optomechanics provides a universal tool to achieve the quantum control of mechanical motion. It does that in devices spanning a vast range of parameters, with mechanical frequencies from a few Hertz to GHz, and with masses from 10-20 g to several kilos. Its underlying ideas can be traced back to the study of gravitational wave antennas, quantum optics, cavity QED and laser cooling which, when combined with the recent availability of advanced micromechanical and nanomechanical devices, opens a path to the realization of macroscopic mechanical systems that operate deep in the quantum regime. At the fundamental level this development paves the way to experiments that will lead to a more profound understanding of quantum mechanics; and from the point of view of applications, quantum optomechanical techniques will provide motion and force sensing near the fundamental limit imposed by quantum mechanics (quantum metrology) and significantly expand the toolbox of quantum information science. After a brief summary of key historical developments, the talk will give a broad overview of the current state of the art of quantum optomechanics, and comment on future prospects both in applied and in fundamental science. Work supported by NSF, ARO and the DARPA QuASAR and ORCHID programs.
A Coupled Nonlinear Spacecraft Attitude Controller/Observer With an Unknown Constant Gyro Bias
NASA Technical Reports Server (NTRS)
Deutschmann, Julie; Sanner, Robert M.; Bauer, Frank H. (Technical Monitor)
2001-01-01
A nonlinear control scheme for attitude control of a spacecraft is combined with a nonlinear gyro bias observer for the case of constant gyro bias. The closed loop system is proven to be globally stable, with zero tracking error, thus proving a separation principle for the given system. The nonlinear observer incorporates persistency of excitation, resulting in exponential convergence of the gyro bias error.
NASA Astrophysics Data System (ADS)
Zhou, Shihua; Song, Guiqiu; Ren, Zhaohui; Wen, Bangchun
2016-03-01
Extensive studies on nonlinear dynamics of gear systems with internal excitation or external excitation respectively have been carried out. However, the nonlinear characteristics of gear systems under combined internal and external excitations are scarcely investigated. An eight-degree-of-freedom(8-DOF) nonlinear spur gear-rotor-bearing model, which contains backlash, transmission error, eccentricity, gravity and input/output torque, is established, and the coupled lateral-torsional vibration characteristics are studied. Based on the equations of motion, the coupled spur gear-rotor-bearing system(SGRBS) is investigated using the Runge-Kutta numerical method, and the effects of rotational speed, error fluctuation and load fluctuation on the dynamic responses are explored. The results show that a diverse range of nonlinear dynamic characteristics such as periodic motion, quasi-periodic motion, chaotic behaviors and impacts exhibited in the system are strongly attributed to the interaction between internal and external excitations. Significantly, the changing rotational speed could effectively control the vibration of the system. Vibration level increases with the increasing error fluctuation. Whereas the load fluctuation has an influence on the nonlinear dynamic characteristics and the increasing excitation force amplitude makes the vibration amplitude increase, the chaotic motion may be restricted. The proposed model and numerical results can be used for diagnosis of faults and vibration control of practical SGRBS.
Homoclinic orbits and chaos in a pair of parametrically driven coupled nonlinear resonators.
Kenig, Eyal; Tsarin, Yuriy A; Lifshitz, Ron
2011-07-01
We study the dynamics of a pair of parametrically driven coupled nonlinear mechanical resonators of the kind that is typically encountered in applications involving microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). We take advantage of the weak damping that characterizes these systems to perform a multiple-scales analysis and obtain amplitude equations, describing the slow dynamics of the system. This picture allows us to expose the existence of homoclinic orbits in the dynamics of the integrable part of the slow equations of motion. Using a version of the high-dimensional Melnikov approach, developed by G. Kovačič and S. Wiggins [Physica D 57, 185 (1992)], we are able to obtain explicit parameter values for which these orbits persist in the full system, consisting of both Hamiltonian and non-Hamiltonian perturbations, to form so-called Šilnikov orbits, indicating a loss of integrability and the existence of chaos. Our analytical calculations of Šilnikov orbits are confirmed numerically. PMID:21867278
Traveling wave solutions in a chain of periodically forced coupled nonlinear oscillators
Duanmu, M.; Whitaker, N.; Kevrekidis, P. G.; Vainchtein, A.; Rubin, J. E.
2016-02-27
Artificial perceptions of light called phosphenes were motivated by earlier studies. We analyze traveling wave solutions in a chain of periodically forced coupled nonlinear oscillators modeling this phenomenon. We examine the discrete model problem in its co-traveling frame and systematically obtain the corresponding traveling waves in one spatial dimension. Direct numerical simulations as well as linear stability analysis are employed to reveal the parameter regions where the traveling waves are stable, and these waves are, in turn, connected to the standing waves analyzed in earlier work. We also consider a two-dimensional extension of the model and demonstrate the robust evolutionmore » and stability of planar fronts. Moreover, our simulations also suggest the radial fronts tend to either annihilate or expand and flatten out, depending on the phase value inside and the parameter regime. Finally, we observe that solutions that initially feature two symmetric fronts with bulged centers evolve in qualitative agreement with experimental observations of phosphenes.« less
Induced N2-cooperative phenomenon in an ensemble of the nonlinear coupled oscillators
NASA Astrophysics Data System (ADS)
Tralle, I.; Ziȩba, P.
2014-04-01
In the article the cooperative N2-effect is considered, that is the radiation whose power is ˜N2, where N is the number of emitters which in this case is equal to the number of nonlinear coupled oscillators. They model the electrons moving in a semiconductor structure with grating (micro-undulator). The suggested effect is in a sense similar to Dicke superradiance, however it is not the spontaneous phase coherence arising in the ensemble of two-level atoms interacting via the emitted electromagnetic field, but rather, the result of interplay of two effects. The first one is the 'pumping wave' acting on the electrons and which is the result of undulator field, while the second is the backward effect of radiation which is produced by electrons moving within such micro-undulator. As a result, the specific phase coherence ('synchronization') develops in the ensemble of emitters and they start to generate as a single oscillating charge Ne, while the power of emitted radiation becomes ˜N2. It is very probable, that the effect can be used for the developing of a new semiconductor-based room temperature source of the GHz and THz-radiation.
A nonlinear electromechanical coupling model for electropore expansion in cell electroporation
NASA Astrophysics Data System (ADS)
Deng, Peigang; Lee, Yi-Kuen; Zhang, Tong-Yi
2014-11-01
Under an electric field, the electric tractions acting on a cell membrane containing a pore-nucleus are investigated by using a nonlinear electromechanical coupling model, in which the cell membrane is treated as a hyperelastic material. Iterations between the electric field and the structure field are performed to reveal the electrical forces exerting on the pore region and the subsequent pore expansion process. An explicit exponential decay of the membrane’s edge energy as a function of pore radius is defined for a hydrophilic pore and the transition energy as a hydrophobic pore converts to a hydrophilic pore during the initial stage of pore formation is investigated. It is found that the edge energy for the creation of an electropore edge plays an important role at the atomistic scale and it determines the hydrophobic-hydrophilic transition energy barrier. Various free energy evolution paths are exhibited, depending on the applied electric field, which provides further insight towards the electroporation (EP) phenomenon. In comparison with previous EP models, the proposed model has the ability to predict the metastable point on the free energy curve that is relevant to the lipid ion channel. In addition, the proposed model can also predict the critical transmembrane potential for the activation of an effective electroporation that is in a good agreement with previously published experimental data.
NASA Astrophysics Data System (ADS)
Zhang, Xiaozhong; Luo, Zhaochu
Size limitation of silicon FET hinders the further scaling down of silicon based CPU. To solve this problem, spin based magnetic logic devices were proposed but almost all of them could not be realized experimentally except for NOT logic operation. A magnetic field controlled reconfigurable semiconductor logic using InSb was reported. However, InSb is very expensive and not compatible with the silicon technology. Based on our Si based magnetoresistance (MR) device, we developed a Si based reconfigurable magnetic logic device, which could do all four Boolean logic operations including AND, OR, NOR and NAND. By coupling nonlinear transport effect of semiconductor and anomalous Hall effect of magnetic material, we propose a PMA material based MR device with a remarkable non local MR of >20000 % at ~1 mT. Based on this MR device, we further developed a PMA material based magnetic logic device which could do all four Boolean logic operations. This makes it possible that magnetic material does both memory and logic. This may result in a memory-logic integrated system leading to a non von Neumann computer
Hornsby, W. A.; Peeters, A. G.; Snodin, A. P.; Casson, F. J.; Camenen, Y.; Szepesi, G.; Siccinio, M.; Poli, E.
2010-09-15
The interaction between small scale turbulence (of the order of the ion Larmor radius) and mesoscale magnetic islands is investigated within the gyrokinetic framework. Turbulence, driven by background temperature and density gradients, over nonlinear mode coupling, pumps energy into long wavelength modes, and can result in an electrostatic vortex mode that coincides with the magnetic island. The strength of the vortex is strongly enhanced by the modified plasma flow response connected with the change in topology, and the transport it generates can compete with the parallel motion along the perturbed magnetic field. Despite the stabilizing effect of sheared plasma flows in and around the island, the net effect of the island is a degradation of the confinement. When density and temperature gradients inside the island are below the threshold for turbulence generation, turbulent fluctuations still persist through turbulence convection and spreading. The latter mechanisms then generate a finite transport flux and, consequently, a finite pressure gradient in the island. A finite radial temperature gradient inside the island is also shown to persist due to the trapped particles, which do not move along the field around the island. In the low collisionality regime, the finite gradient in the trapped population leads to the generation of a bootstrap current, which reduces the neoclassical drive.
Nonlinear optics of hybrid nano-materials under strong coupling conditions
NASA Astrophysics Data System (ADS)
Sukharev, Maxim
2014-03-01
Modern optics fueled with both tremendous advances in nano-fabrication and laser physics is currently experiencing significant growth. We are presently witnessing a unique situation - the research centered at interaction of matter with electromagnetic radiation is fully diving into nanoscale, where one considers purely quantum systems optically driven by nano-materials. The possibilities are vast ranging from fundamental ideas on single atom/molecule optical manipulation, through control of light far below the diffraction limit, to optical engineering and photonic circuitry. Despite progress, the research in optics of quantum media coupled to nano- materials is not complete. Many recent works consider just several quantum emitters driven by near-fields altered by plasmonic materials with a few very promising attempts to include collective effects, which as I will show in this talk play a pivotal role in quantum optics of nano-materials. I will discuss general concepts of nano- plasmonics (one of the most promising sub-fields of nano-optics) with several examples ranging from linear spectroscopy to nonlinear transient absorption.
NASA Astrophysics Data System (ADS)
Song, Byeongju; Park, Byeongjin; Sohn, Hoon; Lim, Cheol-Woo; Park, Jae-Roung
2015-04-01
Rotating shafts in drop lifts of manufacturing facilities are susceptible to fatigue cracks as they are under repetitive heavy loading and high speed spins. However, it is challenging to use conventional contact transducers to monitor these shafts as they are continuously spinning with a high speed. In this study, a noncontact crack detection technique for a rotating shaft is proposed using air-coupled transducers (ACTs). (1) Low frequency (LF) and high frequency (HF) sinusoidal inputs are simultaneously applied to a shaft using two ACTs, respectively. A fatigue crack can provide a mechanism for nonlinear ultrasonic modulation and create spectral sidebands at the modulation frequencies, which are the sum and difference of the two input frequencies Then LF and HF inputs are independently applied to the shaft using each ACT. These three ultrasonic responses are measured using another ACT. (2) The damage index (DI) is defined as the energy of the first sideband components, which corresponding to the frequency sum and difference between HF and LF inputs. (3) Steps 1 and 2 are repeated with various combinations of HF and LF inputs. Crack existence is detected through an outlier analysis of the DIs. The effectiveness of the proposed technique is investigated using a steel shaft with a real fatigue crack.
Yang, Zengtao; Hu, Yuantai; Wang, Ji; Yang, Jiashi
2009-01-01
We point out an implication of the Poynting effect in nonlinear elasticity. It is shown that, due to the Poynting effect, thickness-stretch vibration can be induced in a plate thickness-shear mode resonator of rotated Y-cut quartz when the thickness-shear deformation is no longer infinitesimal. This nonlinear coupling is particularly strong when the frequency of the thickness-stretch mode is twice the frequency of the thickness-shear mode. The induced thickness-stretch vibration affects the operating thickness-shear mode through Mathieu's equation. PMID:19213649
NASA Astrophysics Data System (ADS)
Uhrig, Matthias P.; Kim, Jin-Yeon; Jacobs, Laurence J.
2016-02-01
This research presents a 3D numerical finite element (FE) model which, previously developed, precisely simulates non-contact, air-coupled measurements of nonlinear Rayleigh wave propagation. The commercial FE-solver ABAQUS is used to perform the simulations. First, frequency dependent pressure wave attenuation is investigated numerically to reconstruct the sound pressure distribution along the active surface of the non-contact receiver. Second, constitutive law and excitation source properties are optimized to match nonlinear ultrasonic experimental data. Finally, the FE-model data are fit with analytical solutions showing a good agreement and thus, indicating the significance of the study performed.
Fiber-optic integration and efficient detection schemes for optomechanical resonators
NASA Astrophysics Data System (ADS)
Cohen, Justin D.
With the advent of the laser in the year 1960, the field of optics experienced a renaissance from what was considered to be a dull, solved subject to an active area of development, with applications and discoveries which are yet to be exhausted 55 years later. Light is now nearly ubiquitous not only in cutting-edge research in physics, chemistry, and biology, but also in modern technology and infrastructure. One quality of light, that of the imparted radiation pressure force upon reflection from an object, has attracted intense interest from researchers seeking to precisely monitor and control the motional degrees of freedom of an object using light. These optomechanical interactions have inspired myriad proposals, ranging from quantum memories and transducers in quantum information networks to precision metrology of classical forces. Alongside advances in micro- and nano-fabrication, the burgeoning field of optomechanics has yielded a class of highly engineered systems designed to produce strong interactions between light and motion. Optomechanical crystals are one such system in which the patterning of periodic holes in thin dielectric films traps both light and sound waves to a micro-scale volume. These devices feature strong radiation pressure coupling between high-quality optical cavity modes and internal nanomechanical resonances. Whether for applications in the quantum or classical domain, the utility of optomechanical crystals hinges on the degree to which light radiating from the device, having interacted with mechanical motion, can be collected and detected in an experimental apparatus consisting of conventional optical components such as lenses and optical fibers. While several efficient methods of optical coupling exist to meet this task, most are unsuitable for the cryogenic or vacuum integration required for many applications. The first portion of this dissertation will detail the development of robust and efficient methods of optically coupling
Optomechanical self-oscillations in an anharmonic potential: engineering a nonclassical steady state
NASA Astrophysics Data System (ADS)
Grimm, Manuel; Bruder, Christoph; Lörch, Niels
2016-09-01
We study self-oscillations of an optomechanical system, where coherent mechanical oscillations are induced by a driven optical or microwave cavity, for the case of an anharmonic mechanical oscillator potential. A semiclassical analytical model is developed to characterize the limit cycle for large mechanical amplitudes corresponding to a weak nonlinearity. As a result, we predict conditions to achieve subpoissonian phonon statistics in the steady state, indicating classically forbidden behavior. We compare with numerical simulations and find very good agreement. Our model is quite general and can be applied to other physical systems such as trapped ions or superconducting circuits.
Correlated two-photon transport in a one-dimensional waveguide side-coupled to a nonlinear cavity
Liao Jieqiao; Law, C. K.
2010-11-15
We investigate the transport properties of two photons inside a one-dimensional waveguide side-coupled to a single-mode nonlinear cavity. The cavity is filled with a nonlinear Kerr medium. Based on the Laplace transform method, we present an analytic solution for the quantum states of the two transmitted and reflected photons, which are initially prepared in a Lorentzian wave packet. The solution reveals how quantum correlation between the two photons emerges after the scattering by the nonlinear cavity. In particular, we show that the output wave function of the two photons in position space can be localized in relative coordinates, which is a feature that might be interpreted as a two-photon bound state in this waveguide-cavity system.
NASA Astrophysics Data System (ADS)
Latifi, A.
2016-07-01
A special case of coupled integrable nonlinear equations with a singular dispersion law is derived in the context of the small amplitude limit of general wave equations in a fluid-type warm electrons/cold ions plasma irradiated by a continuous laser beam. This model accounts for a nonlinear mode coupling of the electrostatic wave with the ion sound wave and is shown to be highly unstable. Its instability is understood as a continuous secular transfer of energy from the electrostatic wave to the ion sound wave through the ponderomotive force. The exact asymptotic solution of the system is constructed and shows that the dynamics of the energy transfer results in a singular asymptotic behavior of the ion sound wave, which explains the low penetration of the incident laser beam.
Luo, Zhaochu; Xiong, Chengyue; Zhang, Xu; Guo, Zhen-Gang; Cai, Jianwang; Zhang, Xiaozhong
2016-04-01
The anomalous Hall effect of a magnetic material is coupled to the nonlinear transport effect of a semiconductor material in a simple structure to achieve a large geometric magnetoresistance (MR) based on a diode-assisted mechanism. An extremely large MR (>10(4) %) at low magnetic fields (1 mT) is observed at room temperature. This MR device shows potential for use as a logic gate for the four basic Boolean logic operations. PMID:26857904
NASA Astrophysics Data System (ADS)
Kato, Tsuyoshi; Tanimura, Yoshitaka
2004-01-01
Multidimensional vibrational response functions of a harmonic oscillator are reconsidered by assuming nonlinear system-bath couplings. In addition to a standard linear-linear (LL) system-bath interaction, we consider a square-linear (SL) interaction. The LL interaction causes the vibrational energy relaxation, while the SL interaction is mainly responsible for the vibrational phase relaxation. The dynamics of the relevant system are investigated by the numerical integration of the Gaussian-Markovian Fokker-Planck equation under the condition of strong couplings with a colored noise bath, where the conventional perturbative approach cannot be applied. The response functions for the fifth-order nonresonant Raman and the third-order infrared (or equivalently the second-order infrared and the seventh-order nonresonant Raman) spectra are calculated under the various combinations of the LL and the SL coupling strengths. Calculated two-dimensional response functions demonstrate that those spectroscopic techniques are very sensitive to the mechanism of the system-bath couplings and the correlation time of the bath fluctuation. We discuss the primary optical transition pathways involved to elucidate the corresponding spectroscopic features and to relate them to the microscopic sources of the vibrational nonlinearity induced by the system-bath interactions. Optical pathways for the fifth-order Raman spectroscopies from an "anisotropic" medium were newly found in this study, which were not predicted by the weak system-bath coupling theory or the standard Brownian harmonic oscillator model.
Kato, Tsuyoshi; Tanimura, Yoshitaka
2004-01-01
Multidimensional vibrational response functions of a harmonic oscillator are reconsidered by assuming nonlinear system-bath couplings. In addition to a standard linear-linear (LL) system-bath interaction, we consider a square-linear (SL) interaction. The LL interaction causes the vibrational energy relaxation, while the SL interaction is mainly responsible for the vibrational phase relaxation. The dynamics of the relevant system are investigated by the numerical integration of the Gaussian-Markovian Fokker-Planck equation under the condition of strong couplings with a colored noise bath, where the conventional perturbative approach cannot be applied. The response functions for the fifth-order nonresonant Raman and the third-order infrared (or equivalently the second-order infrared and the seventh-order nonresonant Raman) spectra are calculated under the various combinations of the LL and the SL coupling strengths. Calculated two-dimensional response functions demonstrate that those spectroscopic techniques are very sensitive to the mechanism of the system-bath couplings and the correlation time of the bath fluctuation. We discuss the primary optical transition pathways involved to elucidate the corresponding spectroscopic features and to relate them to the microscopic sources of the vibrational nonlinearity induced by the system-bath interactions. Optical pathways for the fifth-order Raman spectroscopies from an "anisotropic" medium were newly found in this study, which were not predicted by the weak system-bath coupling theory or the standard Brownian harmonic oscillator model. PMID:15267286
Razzak, Md Abdur; Alam, Md Shamsul
2016-01-01
Based on a new trial function, an analytical coupled technique (a combination of homotopy perturbation method and variational method) is presented to obtain the approximate frequencies and the corresponding periodic solutions of the free vibration of a conservative oscillator having inertia and static non-linearities. In some of the previous articles, the first and second-order approximations have been determined by the same method of such nonlinear oscillator, but the trial functions have not been satisfied the initial conditions. It seemed to be a big shortcoming of those articles. The new trial function of this paper overcomes aforementioned limitation. The first-order approximation is mainly considered in this paper. The main advantage of this present paper is, the first-order approximation gives better result than other existing second-order harmonic balance methods. The present method is valid for large amplitudes of oscillation. The absolute relative error measures (first-order approximate frequency) in this paper is 0.00 % for large amplitude A = 1000, while the relative error gives two different second-order harmonic balance methods: 10.33 and 3.72 %. Thus the present method is suitable for solving the above-mentioned nonlinear oscillator. PMID:27119060
Sheng, Shiqi; Tu, Z C
2015-02-01
We present a unified perspective on nonequilibrium heat engines by generalizing nonlinear irreversible thermodynamics. For tight-coupling heat engines, a generic constitutive relation for nonlinear response accurate up to the quadratic order is derived from the stalling condition and the symmetry argument. By applying this generic nonlinear constitutive relation to finite-time thermodynamics, we obtain the necessary and sufficient condition for the universality of efficiency at maximum power, which states that a tight-coupling heat engine takes the universal efficiency at maximum power up to the quadratic order if and only if either the engine symmetrically interacts with two heat reservoirs or the elementary thermal energy flowing through the engine matches the characteristic energy of the engine. Hence we solve the following paradox: On the one hand, the quadratic term in the universal efficiency at maximum power for tight-coupling heat engines turned out to be a consequence of symmetry [Esposito, Lindenberg, and Van den Broeck, Phys. Rev. Lett. 102, 130602 (2009); Sheng and Tu, Phys. Rev. E 89, 012129 (2014)]; On the other hand, typical heat engines such as the Curzon-Ahlborn endoreversible heat engine [Curzon and Ahlborn, Am. J. Phys. 43, 22 (1975)] and the Feynman ratchet [Tu, J. Phys. A 41, 312003 (2008)] recover the universal efficiency at maximum power regardless of any symmetry. PMID:25768487
NASA Astrophysics Data System (ADS)
Michiels, Wim; Nijmeijer, Henk
2009-09-01
We consider the synchronization problem of an arbitrary number of coupled nonlinear oscillators with delays in the interconnections. The network topology is described by a directed graph. Unlike the conventional approach of deriving directly sufficient synchronization conditions, the approach of the paper starts from an exact stability analysis in a (gain, delay) parameter space of a synchronized equilibrium and extracts insights from an analysis of its bifurcations and from the corresponding emerging behavior. Instrumental to this analysis a factorization of the characteristic equation is employed that not only facilitates the analysis and reduces computational cost but also allows to determine the precise role of the individual agents and the topology of the network in the (in)stability mechanisms. The study provides an algorithm to perform a stability and bifurcation analysis of synchronized equilibria. Furthermore, it reveals fundamental limitations to synchronization and it explains under which conditions on the topology of the network and on the characteristics of the coupling the systems are expected to synchronize. In the second part of the paper the results are applied to coupled Lorenz systems. The main results show that for sufficiently large coupling gains, delay-coupled Lorenz systems exhibit a generic behavior that does not depend on the number of systems and the topology of the network, as long as some basic assumptions are satisfied, including the strong connectivity of the graph. Here the linearized stability analysis is strengthened by a nonlinear stability analysis which confirms the predictions based on the linearized stability and bifurcation analysis. This illustrates the usefulness of the exact linearized analysis in a situation where a direct nonlinear stability analysis is not possible or where it yields conservative conditions from which it is hard to get qualitative insights in the synchronization mechanisms and their scaling properties
Macroscopic Quantum Superposition in Cavity Optomechanics.
Liao, Jie-Qiao; Tian, Lin
2016-04-22
Quantum superposition in mechanical systems is not only key evidence for macroscopic quantum coherence, but can also be utilized in modern quantum technology. Here we propose an efficient approach for creating macroscopically distinct mechanical superposition states in a two-mode optomechanical system. Photon hopping between the two cavity modes is modulated sinusoidally. The modulated photon tunneling enables an ultrastrong radiation-pressure force acting on the mechanical resonator, and hence significantly increases the mechanical displacement induced by a single photon. We study systematically the generation of the Yurke-Stoler-like states in the presence of system dissipations. We also discuss the experimental implementation of this scheme. PMID:27152802
Macroscopic Quantum Superposition in Cavity Optomechanics
NASA Astrophysics Data System (ADS)
Liao, Jie-Qiao; Tian, Lin
2016-04-01
Quantum superposition in mechanical systems is not only key evidence for macroscopic quantum coherence, but can also be utilized in modern quantum technology. Here we propose an efficient approach for creating macroscopically distinct mechanical superposition states in a two-mode optomechanical system. Photon hopping between the two cavity modes is modulated sinusoidally. The modulated photon tunneling enables an ultrastrong radiation-pressure force acting on the mechanical resonator, and hence significantly increases the mechanical displacement induced by a single photon. We study systematically the generation of the Yurke-Stoler-like states in the presence of system dissipations. We also discuss the experimental implementation of this scheme.
Optomechanical Magnetometry with a Macroscopic Resonator
NASA Astrophysics Data System (ADS)
Yu, Changqiu; Janousek, Jiri; Sheridan, Eoin; McAuslan, David L.; Rubinsztein-Dunlop, Halina; Lam, Ping Koy; Zhang, Yundong; Bowen, Warwick P.
2016-04-01
We demonstrate a centimeter-scale optomechanical magnetometer based on a crystalline whispering-gallery-mode resonator. The large size of the resonator, with a magnetic-field integration volume of 0.45 cm3 , allows high magnetic-field sensitivity to be achieved in the hertz-to-kilohertz frequency range. A peak sensitivity of 131 pT Hz-1 /2 is reported, in a magnetically unshielded noncryogenic environment using optical power levels beneath 100 μ W . Femtotesla-range sensitivity may be possible in future devices with the further optimization of laser noise and the physical structure of the resonator, allowing applications in high-performance magnetometry.
Quantum optomechanical piston engines powered by heat
NASA Astrophysics Data System (ADS)
Mari, A.; Farace, A.; Giovannetti, V.
2015-09-01
We study two different models of optomechanical systems where a temperature gradient between two radiation baths is exploited for inducing self-sustained coherent oscillations of a mechanical resonator. From a thermodynamic perspective, such systems represent quantum instances of self-contained thermal machines converting heat into a periodic mechanical motion and thus they can be interpreted as nano-scale analogues of macroscopic piston engines. Our models are potentially suitable for testing fundamental aspects of quantum thermodynamics in the laboratory and for applications in energy efficient nanotechnology.
NASA Astrophysics Data System (ADS)
Chai, Jun; Tian, Bo; Wang, Yu-Feng; Zhen, Hui-Ling; Wang, Yun-Po
2015-09-01
In this paper, we investigate the coupled cubic-quintic nonlinear Schrödinger equations with variable coefficients, which describe the effects of quintic nonlinearity for the ultrashort optical pulse propagation in a non-Kerr medium, or in the twin-core nonlinear optical fiber or waveguide. Under certain constraints on the variable coefficients in such equations, mixed-type (bright-dark) vector one- and two-soliton solutions are derived via the Hirota method and symbolic computation, and such vector-soliton solutions are only related to the delayed nonlinear response effect and nonlinearity. Through the graphic analysis, we find that the delayed nonlinear response effect and nonlinearity can both affect the vector-soliton amplitude, while the vector-soliton velocity merely depends on the delayed nonlinear response effect. With the choice on the variable coefficients representing the delayed nonlinear response effect and nonlinearity, interactions between the amplitude- and velocity-unchanging, amplitude-changing, velocity-changing and amplitude- and velocity-changing vector two solitons are obtained. We see that the interaction between the vector two solitons is elastic. We also find that the interaction period of the bound vector solitons decreases as the increase of the delayed nonlinear response effect or increases as the decrease of the delayed nonlinear response effect, but is independent of the nonlinearity.
Generalized dark-bright vector soliton solution to the mixed coupled nonlinear Schrödinger equations
NASA Astrophysics Data System (ADS)
Manikandan, N.; Radhakrishnan, R.; Aravinthan, K.
2014-08-01
We have constructed a dark-bright N-soliton solution with 4N+3 real parameters for the physically interesting system of mixed coupled nonlinear Schrödinger equations. Using this as well as an asymptotic analysis we have investigated the interaction between dark-bright vector solitons. Each colliding dark-bright one-soliton at the asymptotic limits includes more coupling parameters not only in the polarization vector but also in the amplitude part. Our present solution generalizes the dark-bright soliton in the literature with parametric constraints. By exploiting the role of such coupling parameters we are able to control certain interaction effects, namely beating, breathing, bouncing, attraction, jumping, etc., without affecting other soliton parameters. Particularly, the results of the interactions between the bound state dark-bright vector solitons reveal oscillations in their amplitudes under certain parametric choices. A similar kind of effect was also observed experimentally in the BECs. We have also characterized the solutions with complicated structure and nonobvious wrinkle to define polarization vector, envelope speed, envelope width, envelope amplitude, grayness, and complex modulation. It is interesting to identify that the polarization vector of the dark-bright one-soliton evolves on a spherical surface instead of a hyperboloid surface as in the bright-bright case of the mixed coupled nonlinear Schrödinger equations.
Ekedahl, A.; Frincu, B.; Goniche, M.; Hillairet, J.; Petrzilka, V.
2009-11-26
A strong, non-linear degradation of the Lower Hybrid (LH) wave coupling in Tore Supra can be observed when the LH launcher is screened on both sides by additional side limiters, such as side protections of adjacent Ion Cyclotron (IC) antennas. The power reflection coefficient (RC) at the LH grill mouth is estimated to increase from {approx}20% at low power density (<1 MW/m{sup 2}) up to >40% at high power density (>10 MW/m{sup 2}). Such large RC (>40%) is unacceptably high, in particular for long durations. The screening by the additional side limiters reduces the connection length in front of the LH grill, which results in lower {lambda}{sub n}, {lambda}{sub T}, n{sub e} and T{sub e} at the grill. However, the reduction in ne alone is not enough to explain the non-linear behaviour. Modelling with a code that takes into account a ponderomotive force potential [1], depleting the electron density in front of the grill, shows consistent results. In full non-inductive current drive scenarios, the observed degradation in LH coupling is measurable on the LH current drive efficiency, through the increase in coupled LH power required to maintain V{sub Loop} = 0. These results demonstrate thus the importance of being able to control the LH coupling conditions, in order to optimize the efficiency and power handling of LH systems.
NASA Astrophysics Data System (ADS)
Khan, Najeeb Alam; Riaz, Fatima; Sultan, Faqiha
2014-01-01
The boundary layer flow of an electrically conducting couple stress fluid over a non-linear stretching sheet is investigated in the presence of chemical reaction and magnetic field. The governing partial differential equations are reduced to coupled ordinary differential equations (ODEs) with the corresponding appropriate boundary conditions. The analytical solutions of the resulting ODEs have been obtained via the homotopy analysis method (HAM) in the form of series, and their convergence regions can also be found by the convergence control auxiliary parameter. The influence of pertinent parameters such as the magnetic, the couple stress and the chemical reaction parameters are discussed on the velocity and concentration profiles of the fluid. Hence, a comparison has been made with the previous results in the literature as a limiting case of the considered problem.
Sensing feeble microwave signals via an optomechanical transducer
NASA Astrophysics Data System (ADS)
Zhang, Keye; Bariani, Francesco; Dong, Ying; Zhang, Weiping; Meystre, Pierre
2015-05-01
Due to their low energy content microwave signals at the single-photon level are extremely challenging to measure. Guided by recent progress in single-photon optomechanics and hybrid optomechanical systems, we propose a multimode optomechanical transducer that can detect intensities significantly below the single-photon level via off-resonant adiabatic transfer of the microwave signal to the optical frequency domain where the measurement is then performed. The influence of intrinsic quantum and thermal fluctuations on the performance of this detector are considered in detail. We acknowledge financial support from National Basic Research Program of China, NSF, ARO and the DARPA QuaSAR and ORCHID programs.
NASA Astrophysics Data System (ADS)
Li, Jiahua; Zhan, Xiaogui; Ding, Chunling; Zhang, Duo; Wu, Ying
2015-10-01
We present a perturbation technique to study the linear and nonlinear output characteristics of coherent photon transport in a parity-time (PT )-symmetric double-microcavity system where one passive cavity contains a single quantum emitter. It is found that (i) for the linear transmission of a low-power input probe field, the output spectra of the proposed PT -symmetric system exhibit a single transparent resonance dip and two symmetric, strongly amplifying sidebands, i.e., an inverted dipole-induced transparency; and (ii) for the nonlinear transmission of the input probe field, giant optical third-order nonlinearities with high linear transmission rate and vanishing nonlinear absorption can be achieved efficiently when the system parameters are tuned properly so that a PT -symmetry phase transition occurs. The obtained results can be useful for quantum information processing, quantum nondemolition measurements of photons, and optical signal processing.
Nonequilibrium quantum dynamics in optomechanical systems
NASA Astrophysics Data System (ADS)
Patil, Yogesh Sharad; Cheung, Hil F. H.; Shaffer, Airlia; Wang, Ke; Vengalattore, Mukund
2016-05-01
The thermalization dynamics of isolated quantum systems has so far been explored in the context of cold atomic systems containing a large number of particles and modes. Quantum optomechanical systems offer prospects of studying such dynamics in a qualitatively different regime - with few individually addressable modes amenable to continuous quantum measurement and thermalization times that vastly exceed those observed in cold atomic systems. We have experimentally realized a dynamical continuous phase transition in a quantum compatible nondegenerate mechanical parametric oscillator. This system is formally equivalent to the optical parametric amplifiers whose dynamics have been a subject of intense theoretical study. We experimentally verify its phase diagram and observe nonequilibrium behavior that was only theorized, but never directly observed, in the context of optical parametric amplifiers. We discuss prospects of using nonequilibrium protocols such as quenches in optomechanical systems to amplify weak nonclassical correlations and to realize macroscopic nonclassical states. This work was supported by the DARPA QuASAR program through a Grant from the ARO and the ARO MURI on non-equilibrium manybody dynamics.
Opto-mechanical door locking system
NASA Astrophysics Data System (ADS)
Patil, Saurabh S.; Rodrigues, Vanessa M.; Patil, Ajeetkumar; Chidangil, Santhosh
2015-09-01
We present an Opto-mechanical Door Locking System which is an optical system that combines a simple combination of a coherent light source (Laser) and a photodiode based sensor with focus toward security applications. The basic construct of the KEY comprises a Laser source in a cylindrical enclosure that slides perfectly into the LOCK. The Laser is pulsed at a fixed encrypted frequency unique to that locking system. Transistor-transistor logic (TTL) circuitry is used to achieve encryption. The casing of the key is designed in such a way that it will power the pulsing laser only when the key is inserted in the slot provided for it. The Lock includes a photo-sensor that will convert the detected light intensity to a corresponding electrical signal by decrypting the frequency. The lock also consists of a circuit with a feedback system that will carry the digital information regarding the encryption frequency code. The information received from the sensor is matched with the stored code; if found a perfect match, a signal will be sent to the servo to unlock the mechanical lock or to carry out any other operation. This technique can be incorporated in security systems for residences and safe houses, and can easily replace all conventional locks which formerly used fixed patterns to unlock. The major advantage of this proposed optomechanical system over conventional ones is that it no longer relies on a solid/imprinted pattern to perform its task and hence makes it almost impossible to tamper with.
Weak concentration and wave operator for a 3D coupled nonlinear Schrödinger system
NASA Astrophysics Data System (ADS)
Pastor, Ademir
2015-02-01
Reported in this paper are results concerning the Cauchy problem and the dynamics for a cubic nonlinear Schrödinger system arising in nonlinear optics. A sharp criterion is given concerned with the dichotomy global existence versus finite time blow-up. When a radial solution blows up in finite time, we prove the concentration in the critical Lebesgue space. Sufficient condition for the scattering and the construction of the wave operator in the energy space is also provided.
NASA Astrophysics Data System (ADS)
Yaman, Mustafa; Sen, Sadri
2007-02-01
In this study, the nonlinear behavior of a slender beam coupled with a pendulum is investigated numerically in terms of different system parameters. The structure consisting of a cantilever beam of varying orientation with a tip mass and pendulum which is attached to the tip mass as a passive vibration absorber is subjected to a vertical sinusoidal base excitation. The Euler-Bernoulli theory for the slender beam is used to derive the governing non-linear partial differential equation. The non-linear terms arising from inertia, curvature and axial displacement caused by large transverse deflections, and the coupling between the primary structure and absorber are retained up to third order. When the structure is forced in the neighborhood of its resonance, the pendulum absorber (controller) reduces the structure response because of autoparametric interaction between the beam and pendulum. Autoparametric interaction in the system was investigated by varying orientation angles, the forcing amplitude, the internal frequency ratio, and the mass ratio in the neighborhood of the autoparametric resonance. The absorption regions were defined with respect to the system parameters for the passive vibration absorber.
NASA Astrophysics Data System (ADS)
Hussien, Mahmoud N.; Tobita, Tetsuo; Iai, Susumu
The non-linear response of coupled soil-pile-structure systems to seismic loading is parametrically studied in the frequency domain using two-dimensional (2D) finite elements (FE). The soil-pile interaction in three dimensions (3D) is idealized in the 2D type using soil-pile interaction springs with non-linear hysteretic load displacement relationships. The system under investigation comprises of a single degree of freedom structure supported by an end-bearing single pile founded in a homogenous sand layer over rigid rock. Comparisons with established results from the literature suggest that the adopted FE model reasonably captures the essential features of the seismic response of the coupled soil-pile-structure system. Numerical results demonstrate the strong influence on the effective natural period of the foundation properties. The effect of non-linear soil behavior and soil profile as well as the frequency content of excitation on both kinematic and inertial interactions is illustrated. The relative contributions of kinematic and inertial interaction to the development of dynamic pile bending are clarified.
NASA Astrophysics Data System (ADS)
García, Hermes A.; Guerrero-Bolaño, Francisco J.; Obregón-Neira, Nelson
2010-05-01
Due to both mathematical tractability and efficiency on computational resources, it is very common to find in the realm of numerical modeling in hydro-engineering that regular linearization techniques have been applied to nonlinear partial differential equations properly obtained in environmental flow studies. Sometimes this simplification is also made along with omission of nonlinear terms involved in such equations which in turn diminishes the performance of any implemented approach. This is the case for example, for contaminant transport modeling in streams. Nowadays, a traditional and one of the most common used water quality model such as QUAL2k, preserves its original algorithm, which omits nonlinear terms through linearization techniques, in spite of the continuous algorithmic development and computer power enhancement. For that reason, the main objective of this research was to generate a flexible tool for non-linear water quality modeling. The solution implemented here was based on two genetic algorithms, used in a nested way in order to find two different types of solutions sets: the first set is composed by the concentrations of the physical-chemical variables used in the modeling approach (16 variables), which satisfies the non-linear equation system. The second set, is the typical solution of the inverse problem, the parameters and constants values for the model when it is applied to a particular stream. From a total of sixteen (16) variables, thirteen (13) was modeled by using non-linear coupled equation systems and three (3) was modeled in an independent way. The model used here had a requirement of fifty (50) parameters. The nested genetic algorithm used for the numerical solution of a non-linear equation system proved to serve as a flexible tool to handle with the intrinsic non-linearity that emerges from the interactions occurring between multiple variables involved in water quality studies. However because there is a strong data limitation in
NASA Astrophysics Data System (ADS)
Bellizzi, Sergio; Côte, Renaud; Pachebat, Marc
2013-04-01
In this paper, forced responses are investigated in a two degree-of-freedom linear system with a linear coupling to a Non-linear Energy Sink (NES) subjected to quasi-periodic excitation. The quasi-periodic regimes associated to quasi-periodic forcing in the regime of 1:1-1:1 are studied analytically using the complexification method combined to the averaging method in terms of multi-time parameter. Local bifurcations of the quasi-periodic regimes are also analyzed using the excitation frequencies as control parameters. The nonlinear differential system is also solved numerically in time domain and the responses are analyzed in view of the analytical results. Stable and unstable quasi-periodic responses are found in good agreement with the analytical study, and strongly modulated responses are noticed. We observe that a single NES can be efficient for the reduction of two resonance peaks even if they are well separated, incommensurable, and excited simultaneously.
Greco, M.; Lugni, C.; Faltinsen, O. M.
2015-01-01
Occurrence and features of parametric roll (PR) on a weather-vaning floating production storage and offloading (FPSO) platform with a turret single-point mooring-line system are examined. The main focus is on the relevance of motions coupling and nonlinear effects on this phenomenon and on more general unstable conditions as well as on the occurrence and severity of water on deck. This work was motivated by recent experiments on an FPSO model without mooring systems highlighting the occurrence of parametric resonance owing to roll–yaw coupling. A three-dimensional numerical hybrid potential-flow seakeeping solver was able to capture this behaviour. The same method, extended to include the mooring lines, is adopted here to investigate the platform behaviour for different incident wavelengths, steepnesses, headings, locations of the turret and pretensions. From the results, sway and yaw tend to destabilize the system, also bringing chaotic features. The sway–roll–yaw coupling widens the existence region of PR resonance and increases PR severity; it also results in a larger amount of shipped water, especially at smaller wavelength-to-ship length ratio and larger steepness. The chaotic features are excited when a sufficiently large yaw amplitude is reached. Consistently, a simplified stability analysis showed the relevance of nonlinear-restoring coefficients, first those connected with the sway–yaw coupling then those associated with the roll–yaw coupling, both destabilizing. From the stability analysis, the system is unstable for all longitudinal locations of the turret and pre-tensions examined, but the instability weakens as the turret is moved forward, and the pre-tension is increased. The use of a suitable dynamic-positioning system can control the horizontal motions, avoiding the instability. PMID:25512590
Greco, M; Lugni, C; Faltinsen, O M
2015-01-28
Occurrence and features of parametric roll (PR) on a weather-vaning floating production storage and offloading (FPSO) platform with a turret single-point mooring-line system are examined. The main focus is on the relevance of motions coupling and nonlinear effects on this phenomenon and on more general unstable conditions as well as on the occurrence and severity of water on deck. This work was motivated by recent experiments on an FPSO model without mooring systems highlighting the occurrence of parametric resonance owing to roll-yaw coupling. A three-dimensional numerical hybrid potential-flow seakeeping solver was able to capture this behaviour. The same method, extended to include the mooring lines, is adopted here to investigate the platform behaviour for different incident wavelengths, steepnesses, headings, locations of the turret and pretensions. From the results, sway and yaw tend to destabilize the system, also bringing chaotic features. The sway-roll-yaw coupling widens the existence region of PR resonance and increases PR severity; it also results in a larger amount of shipped water, especially at smaller wavelength-to-ship length ratio and larger steepness. The chaotic features are excited when a sufficiently large yaw amplitude is reached. Consistently, a simplified stability analysis showed the relevance of nonlinear-restoring coefficients, first those connected with the sway-yaw coupling then those associated with the roll-yaw coupling, both destabilizing. From the stability analysis, the system is unstable for all longitudinal locations of the turret and pre-tensions examined, but the instability weakens as the turret is moved forward, and the pre-tension is increased. The use of a suitable dynamic-positioning system can control the horizontal motions, avoiding the instability. PMID:25512590
Cooling of a mirror in cavity optomechanics with a chirped pulse
Liao, Jie-Qiao; Law, C. K.
2011-11-15
We investigate the response of a harmonically confined mirror to an optical pulse in cavity optomechanics. We show that when the pulsed coupling strength takes the form of a chirped pulse, thermal fluctuations of the mirror can be significantly transferred to the cavity field. In addition, the frequency modulation of the pulse could enable a better cooling performance by suppressing the sensitivity of the dependence of detuning and pulse areas. Using numerical investigations, we find that the pulsed cooling is mainly limited by the cavity-field decay rate.
Storage and retrieval of quantum information with a hybrid optomechanics-spin system
NASA Astrophysics Data System (ADS)
Feng, Zhi-Bo; Zhang, Jian-Qi; Yang, Wan-Li; Feng, Mang
2016-08-01
We explore an efficient scheme for transferring the quantum state between an optomechanical cavity and an electron spin of diamond nitrogen-vacancy center. Assisted by a mechanical resonator, quantum information can be controllably stored (retrieved) into (from) the electron spin by adjusting the external field-induced detuning or coupling. Our scheme connects effectively the cavity photon and the electron spin and transfers quantum states between two regimes with large frequency difference. The experimental feasibility of our protocol is justified with accessible laboratory parameters.
All-optical transistor based on a cavity optomechanical system with a Bose-Einstein condensate
Chen, Bin; Jiang, Cheng; Li, Jin-Jin; Zhu, Ka-Di
2011-11-15
We propose a scheme of an all-optical transistor based on a coupled Bose-Einstein condensate cavity system. The calculated results show that, in such an optomechanical system, the transmission of the probe beam is strongly dependent on the optical pump power. Therefore, the optical pump field can serve as a ''gate'' field of the transistor, effectively controlling the propagation of the probe field (the ''signal'' field). The scheme proposed here may have potential applications in optical communication and quantum information processing.