scholarly journals Enhanced ion–cavity coupling through cavity cooling in the strong coupling regime

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Costas Christoforou ◽  
Corentin Pignot ◽  
Ezra Kassa ◽  
Hiroki Takahashi ◽  
Matthias Keller
Keyword(s):  
Laser Cooling ◽  
Ion Traps ◽  
Geometric Constraints ◽  
The Other ◽  
Strong Coupling Regime ◽  
Quantum Networks ◽  
Optical Cavities ◽  
Cavity Coupling ◽  
Cavity Cooling ◽  
Doppler Cooling

Abstract Incorporating optical cavities in ion traps is becoming increasingly important in the development of photonic quantum networks. However, the presence of the cavity can hamper efficient laser cooling of ions because of geometric constraints that the cavity imposes and an unfavourable Purcell effect that can modify the cooling dynamics substantially. On the other hand the coupling of the ion to the cavity can also be exploited to provide a mechanism to efficiently cool the ion. In this paper we demonstrate experimentally how cavity cooling can be implemented to improve the localisation of the ion and thus its coupling to the cavity. By using cavity cooling we obtain an enhanced ion–cavity coupling of $$2\pi \times (16.7\pm 0.1)$$ 2 π × ( 16.7 ± 0.1 ) MHz, compared with $$2\pi \times (15.2\pm 0.1)$$ 2 π × ( 15.2 ± 0.1 ) MHz when using only Doppler cooling.

Cavity Cooling Below the Recoil Limit

Science ◽  
2012 ◽  
Vol 337 (6090) ◽  
pp. 75-78 ◽  
Author(s):  
Matthias Wolke ◽  
Julian Klinner ◽  
Hans Keßler ◽  
Andreas Hemmerich
Keyword(s):  
Laser Cooling ◽  
Single Photon ◽  
Einstein Condensate ◽  
Purcell Factor ◽  
Optical Cavities ◽  
Bose Einstein Condensate ◽  
Cavity System ◽  
Bose Einstein ◽  
Cavity Cooling ◽  
Conventional Laser

Conventional laser cooling relies on repeated electronic excitations by near-resonant light, which constrains its area of application to a selected number of atomic species prepared at moderate particle densities. Optical cavities with sufficiently large Purcell factors allow for laser cooling schemes, avoiding these limitations. Here, we report on an atom-cavity system, combining a Purcell factor above 40 with a cavity bandwidth below the recoil frequency associated with the kinetic energy transfer in a single photon scattering event. This lets us access a yet-unexplored regime of atom-cavity interactions, in which the atomic motion can be manipulated by targeted dissipation with sub-recoil resolution. We demonstrate cavity-induced heating of a Bose-Einstein condensate and subsequent cooling at particle densities and temperatures incompatible with conventional laser cooling.

The Conceptual Design of Differential Mechanisms

2013 ◽  
Vol 284-287 ◽  
pp. 973-978
Author(s):  
Chia Chun Chu
Keyword(s):  
Conceptual Design ◽  
Design Process ◽  
Degrees Of Freedom ◽  
Geometric Constraints ◽  
The Other ◽  
Design Approach ◽  
Process Step ◽  
Two Degrees Of Freedom ◽  
Number Synthesis

The purpose of this paper is to present a design approach based on the geometric constraints of joints for synthesizing differential mechanisms with two degrees-of-freedom, including some mechanisms with the same functions but distinct structures. The concept of virtual axes is presented. And, there are five steps in the design process. Step 1 is to decide fundamental entities by the properties of existing mechanisms and the technique of number synthesis, and 10 suitable fundamental entities of differential mechanisms are available. Step 2 is to compose geometric constraints, and 14 items are obtained. Step 3 is to compose links, and 15 items are derived. Step 4 is to assign fixed constraints for inputs or outputs, and 15 results are found. The final step is to particularize the obtained events by the properties of existing mechanisms and the structures of fundamental entities. As a result, 8 feasible results for differential mechanisms with two degrees-of-freedom and two basic loops are obtained in which 2 are existing designs and the other 6 are novel.

scholarly journals Optical system for Doppler cooling of trapped calcium ions

2017 ◽  
Vol 9 (4) ◽  
pp. 119 ◽  
Author(s):  
Lukasz Klosowski ◽  
Katarzyna Pleskacz ◽  
Szymon Wójtewicz ◽  
Daniel Lisak ◽  
Mariusz Piwiński
Keyword(s):  
Charged Particle ◽  
Optical System ◽  
Laser Cooling ◽  
Calcium Ions ◽  
Impact Ionization ◽  
Mode Locking ◽  
Trapped Ions ◽  
Slowing Down ◽  
Product Ions ◽  
Doppler Cooling

In the experiments involving trapped ions, application of a cooling procedure is required. The optical Doppler scheme is one of the most commonly used methods for slowing down the ions motion. In this paper we present an optical system sufficient for cooling calcium ions in such scheme. The system allows also for optical detection of the trapped ions. Full Text: PDF ReferencesF. Major, V. Gheorghe, and G. Werth, Charged Particle traps, Physics and Techniques of Charged Particle Field Confinement (Springer 2005). DirectLink Ł. Kłosowski, M. Piwiński, and M. Drewsen, "Integral electron impact ionization cross section of molecules through Coulomb crystallization of the product ions", J. Phys. Conf. Ser. 635, 072003 (2015) CrossRef D. J. Wineland and Wayne M. Itano, "Laser cooling of atoms", Phys. Rev. A 20, 1521 (1979) CrossRef R. Drever et al., "Laser phase and frequency stabilization using an optical resonator", Appl. Phys. B 31, 97 (1983) CrossRef P. W. Smith, "Mode-locking of lasers", Proceedings of the IEEE 58, 1342 (1970) CrossRef S. Stenholm, "The semiclassical theory of laser cooling", Rev. Mod. Phys. 58, 699 (1986) CrossRef

scholarly journals Entropic analysis of optomechanical entanglement for a nanomechanical resonator coupled to an optical cavity field

2021 ◽  
Vol 4 (3) ◽  
Author(s):  
Jeong Ryeol Choi
Keyword(s):  
Coupling Strength ◽  
Optical Cavity ◽  
Von Neumann Entropy ◽  
Strong Coupling Regime ◽  
Optical Frequency ◽  
Cavity Field ◽  
Quantum Networks ◽  
Nanomechanical Resonator ◽  
Von Neumann ◽  
Quantum Science

We investigate entanglement dynamics for a nanomechanical resonator coupled to an optical cavity field through the analysis of the associated entanglement entropies. The effects of time variation of several parameters, such as the optical frequency and the coupling strength, on the evolution of entanglement entropies are analyzed. We consider three kinds of entanglement entropies as the measures of the entanglement of subsystems, which are the linear entropy, the von Neumann entropy, and the Rényi entropy. The analytic formulae of these entropies are derived in a rigorous way using wave functions of the system. In particular, we focus on time behaviors of entanglement entropies in the case where the optical frequency is modulated by a small oscillating factor. We show that the entanglement entropies emerge and increase as the coupling strength grows from zero. The entanglement entropies fluctuate depending on the adiabatic variation of the parameters and such fluctuations are significant especially in the strong coupling regime. Our research may deepen the understanding of the optomechanical entanglement, which is crucial in realizing hybrid quantum-information protocols in quantum computation, quantum networks, and other domains in quantum science.

scholarly journals Polariton hyperspectral imaging of two-dimensional semiconductor crystals

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Christian Gebhardt ◽  
Michael Förg ◽  
Hisato Yamaguchi ◽  
Ismail Bilgin ◽  
Aditya D. Mohite ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Transition Metal Dichalcogenides ◽  
Binding Energies ◽  
Strong Coupling Regime ◽  
Two Dimensional ◽  
Strong Light ◽  
Optical Cavities ◽  
Metal Dichalcogenides ◽  
High Level ◽  
Micro Cavity

Abstract Atomically thin crystals of transition metal dichalcogenides (TMDs) host excitons with strong binding energies and sizable light-matter interactions. Coupled to optical cavities, monolayer TMDs routinely reach the regime of strong light-matter coupling, where excitons and photons admix coherently to form polaritons up to room temperature. Here, we explore the two-dimensional nature of TMD polaritons with scanning-cavity hyperspectral imaging. We record a spatial map of polariton properties of extended WS2 monolayers coupled to a tunable micro cavity in the strong coupling regime, and correlate it with maps of exciton extinction and fluorescence taken from the same flake with the cavity. We find a high level of homogeneity, and show that polariton splitting variations are correlated with intrinsic exciton properties such as oscillator strength and linewidth. Moreover, we observe a deviation from thermal equilibrium in the resonant polariton population, which we ascribe to non-Markovian polariton-phonon coupling. Our measurements reveal a promisingly consistent polariton landscape, and highlight the importance of phonons for future polaritonic devices.

scholarly journals Laser Manipulation of Atoms and Atom Optics

1995 ◽  
Vol 48 (2) ◽  
pp. 267 ◽  
Author(s):  
Yu-Zhu Wang ◽  
Liang Liu
Keyword(s):  
Standing Wave ◽  
Laser Cooling ◽  
Atomic Beam ◽  
Basic Concept ◽  
Light Field ◽  
Atom Optics ◽  
Diffuse Light ◽  
Laser Manipulation ◽  
Doppler Cooling

In this paper experiments on laser cooling, collimation and manipulation of a sodium atomic beam, such as the transverse collimation and decollimation of an atomic beam by a standing wave or a misaligned standing wave, longitudinal cooling of an atomic beam by a diffuse light field, sub-Doppler cooling in a blue detuned standing wave, are reported. The basic concept on atom optics is developed. An experiment on a method for the injection of atoms into an atomic cavity is also discussed.

scholarly journals Comparative Numerical Studies of Ion Traps with Integrated Optical Cavities

2016 ◽  
Vol 6 (4) ◽  
Author(s):  
Nina Podoliak ◽  
Hiroki Takahashi ◽  
Matthias Keller ◽  
Peter Horak
Keyword(s):  
Ion Traps ◽  
Optical Cavities ◽  
Numerical Studies ◽  
Integrated Optical

scholarly journals Circular dichroism mode splitting and bounds to its enhancement with cavity-plasmon-polaritons

Nanophotonics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 283-293 ◽  
Author(s):  
Denis G. Baranov ◽  
Battulga Munkhbat ◽  
Nils Odebo Länk ◽  
Ruggero Verre ◽  
Mikael Käll ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Coupled System ◽  
Plasmonic Nanoparticles ◽  
Strong Coupling Regime ◽  
Optical Cavities ◽  
Mode Splitting ◽  
Fabry Perot ◽  
Theoretical Predictions ◽  
Light Matter Interaction ◽  
Circular Dichroïsm

AbstractGeometrical chirality is a widespread phenomenon that has fundamental implications for discriminating enantiomers of biomolecules. In order to enhance the chiral response of the medium, it has been suggested to couple chiral molecules to resonant optical cavities in order to enhance the circular dichroism (CD) signal at the resonant frequency of the cavity. Here, we studied a distinctly different regime of chiral light-matter interaction, wherein the CD signal of a chiral medium splits into polaritonic modes by reaching the strong coupling regime with an optical microcavity. Specifically, we show that by strongly coupling chiral plasmonic nanoparticles to a non-chiral Fabry-Pérot microcavity one can imprint the mode splitting on the CD spectrum of the coupled system and thereby effectively shift the initial chiral resonance to a different energy. We first examined the effect with the use of analytical transfer-matrix method as well as numerical finite-difference time-domain (FDTD) simulations. Furthermore, we confirmed the validity of theoretical predictions in a proof-of-principle experiment involving chiral plasmonic nanoparticles coupled to a Fabry-Pérot microcavity.

scholarly journals Evidence for S2 flexibility by direct visualization of quantum dot–labeled myosin heads and rods within smooth muscle myosin filaments moving on actin in vitro

2021 ◽  
Vol 153 (3) ◽  
Author(s):  
Richard K. Brizendine ◽  
Murali Anuganti ◽  
Christine R. Cremo
Keyword(s):  
Coiled Coil ◽  
Geometric Constraints ◽  
The Other ◽  
Direct Visualization ◽  
Myosin Filaments ◽  
Different Color ◽  
Distance Working ◽  
Muscle Myosin ◽  
Kinetics Of

Myosins in muscle assemble into filaments by interactions between the C-terminal light meromyosin (LMM) subdomains of the coiled-coil rod domain. The two head domains are connected to LMM by the subfragment-2 (S2) subdomain of the rod. Our mixed kinetic model predicts that the flexibility and length of S2 that can be pulled away from the filament affects the maximum distance working heads can move a filament unimpeded by actin-attached heads. It also suggests that it should be possible to observe a head remain stationary relative to the filament backbone while bound to actin (dwell), followed immediately by a measurable jump upon detachment to regain the backbone trajectory. We tested these predictions by observing filaments moving along actin at varying ATP using TIRF microscopy. We simultaneously tracked two different color quantum dots (QDs), one attached to a regulatory light chain on the lever arm and the other attached to an LMM in the filament backbone. We identified events (dwells followed by jumps) by comparing the trajectories of the QDs. The average dwell times were consistent with known kinetics of the actomyosin system, and the distribution of the waiting time between observed events was consistent with a Poisson process and the expected ATPase rate. Geometric constraints suggest a maximum of ∼26 nm of S2 can be unzipped from the filament, presumably involving disruption in the coiled-coil S2, a result consistent with observations by others of S2 protruding from the filament in muscle. We propose that sufficient force is available from the working heads in the filament to overcome the stiffness imposed by filament-S2 interactions.

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