Energy landscape of colloidal dumbbells in a periodic distribution of light

Sarmiento-Gómez, Erick; Rivera-Morán, J. A.; Arauz‐Lara, José Luis

doi:10.1039/c9sm00472f

Cited by 5 publications

(6 citation statements)

References 32 publications

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“…For our experimental conditions, the set-up is able to produce fringes between 1.3 and 6.0 μm by varying the position of the prism mirror. As shown before [34], if the periodicity of the light distribution is larger than the size of the particle, such a distribution produces a periodical potential with the same periodicity, where the bright fringes corresponds to the minima in the potential. For this study, the periodicity of the distribution of light was set to 1 µm.…”

Section: Experimental Methodsmentioning

confidence: 54%

“…The experimental set up for the light potential is based on the interference of two beams in the plane of the sample, which produces a periodical array of bright fringes of a specific width. This experimental setup has been fully described elsewhere [34], here we only discuss the main points. The laser beam used has a spectral width <200 kHz (Azur Light Systems) and range powers between 40 and 500 mW.…”

Section: Experimental Methodsmentioning

confidence: 99%

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On the Time Transition Between Short- and Long-Time Regimes of Colloidal Particles in External Periodic Potentials

et al. 2021

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The dynamics of colloidal particles at infinite dilution, under the influence of periodic external potentials, is studied here via experiments and numerical simulations for two representative potentials. From the experimental side, we analyzed the motion of a colloidal tracer in a one-dimensional array of fringes produced by the interference of two coherent laser beams, providing in this way an harmonic potential. The numerical analysis has been performed via Brownian dynamics (BD) simulations. The BD simulations correctly reproduced the experimental position- and time-dependent density of probability of the colloidal tracer in the short-times regime. The long-time diffusion coefficient has been obtained from the corresponding numerical mean square displacement (MSD). Similarly, a simulation of a random walker in a one dimensional array of adjacent cages with a probability of escaping from one cage to the next cage is one of the most simple models of a periodic potential, displaying two diffusive regimes separated by a dynamical caging period. The main result of this study is the observation that, in both potentials, it is seen that the critical time t*, defined as the specific time at which a change of curvature in the MSD is observed, remains approximately constant as a function of the height barrier U0 of the harmonic potential or the associated escape probability of the random walker. In order to understand this behavior, histograms of the first passage time of the tracer have been calculated for several height barriers U0 or escape probabilities. These histograms display a maximum at the most likely first passage time t′, which is approximately independent of the height barrier U0, or the associated escape probability, and it is located very close to the critical time t*. This behavior suggests that the critical time t*, defining the crossover between short- and long-time regimes, can be identified as the most likely first passage time t′ as a first approximation.

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Section: Experimental Methodsmentioning

confidence: 54%

Section: Experimental Methodsmentioning

confidence: 99%

On the Time Transition Between Short- and Long-Time Regimes of Colloidal Particles in External Periodic Potentials

et al. 2021

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“…Thus, based on p hop (t), angular jumps can be identified but they seem uncorrelated with the translational motion. Angular jumps have previously been observed for the motion of dimers exposed to a periodic potential energy landscape created by a fringe pattern [43]. In this study, rotations within the one-dimensional potential minima have been experimentally observed and theoretically predicted to occur through discrete rotational jumps.…”

Section: Angular Jumpsmentioning

confidence: 68%

“…This potential was imposed on the particles by applying a random light field and the magnitude of the modulations was controlled through the laser intensity P L ( Figure 1B). A convolution with the particle volume results in the potential energy landscape [34,43,49].…”

Section: Resultsmentioning

confidence: 99%

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Diffusion of Anisotropic Particles in Random Energy Landscapes—An Experimental Study

et al. 2020

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If a colloidal particle is exposed to an external field, its Brownian motion is modified. In the case of an anisotropic particle, the external potential might not only affect its translation but also its rotation. We experimentally investigate the dynamics of a trimer, which consists of three spherical particles, within a random potential energy landscape. This energy landscape has energy values drawn from a Gamma distribution, a spatial correlation length similar to the particle size and is realized by a random light field, that is a laser speckle pattern. The particle translation and rotation are quantified by the mean squared (angular) displacement, the van Hove function and other observable quantities. The translation shows an intermediate subdiffusive regime and a long-time diffusion that slows down upon increasing the modulation of the potential. In contrast, the mean squared angular displacement exhibits only small deviations from a linear time dependence but a more detailed analysis reveals discrete angular jumps reflecting the symmetry of the trimer. A coupling between the translation and rotation is observed and found to depend on the length scale.

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Light‐Directed Assembly of Colloidal Matter

Chen

Lin

et al. 2022

Adv Funct Materials

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The assembly of colloidal particles into 2D or 3D superstructures is significant as the colloidal assembly exhibits collective behavior beyond the sum of single particles. Technically, colloidal particles can either self‐assemble when thermodynamic equilibrium is reached, or directed into specific assembly under external stimulus, such as electric, magnetic, acoustic, or light field. Specifically, light can be focused locally and manipulated in a precise manner, providing the possibility to tailor the assembly kinetics in different degrees of freedom. The understanding of light–matter interaction during the assembly process is challenging but critical for the design and fabrication of diverse colloidal superstructures. In this review, these particles are treated as artificial atoms at colloidal scale to mimic the organization of matter. From this aspect, the light‐directed assembly process is discussed on the basis of the roles of light, including light‐directed nucleation, diffusion, interparticle bonding, and phase control. Beyond what has been observed at atomic scale, colloidal atoms exhibit diversity in size, shape, and composition, and their bonding force is irrelevant to the electronic state, which enriches the geometric complexity of colloidal matter. Finally, the authors summarize the emerging applications of these colloidal superstructures in nanophotonics, nanocatalysis, and nanomedicine, and outline the major challenge and future development.

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Energy landscape of colloidal dumbbells in a periodic distribution of light

Abstract: Using a ray tracing calculation, the energy landscape of dumbbells, made of spherical colloidal particles, interacting with a periodic distribution of light is calculated.

Cited by 5 publications

References 32 publications

On the Time Transition Between Short- and Long-Time Regimes of Colloidal Particles in External Periodic Potentials

On the Time Transition Between Short- and Long-Time Regimes of Colloidal Particles in External Periodic Potentials

Diffusion of Anisotropic Particles in Random Energy Landscapes—An Experimental Study

Light‐Directed Assembly of Colloidal Matter

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