National Repository of Grey Literature 23 records found  previous11 - 20next  jump to record: Search took 0.01 seconds. 
Noise to signal transition: work obtained from noise studied by the optical tweezers
Šiler, Martin ; Filip, R. ; Jákl, Petr ; Brzobohatý, Oto ; Zemánek, Pavel
The noise-to-signal transitions are very interesting processes in physics as they might transform environmental noise to useful mechanical effects. In this contribution we introduce the problem of stochastic noise-to-signal transition of overdamped Brownian motion of a particle in the cubic potential. The particle reaches thermal equilibrium with its environment in the quadratic potential which is suddenly swapped to the cubic potential. We predict simultaneous increase of both the displacement and signal-to-noise ratio in the cubic potential for the position linearly powered by temperature of the particle environment. Further, we propose a feasible experimental setup for proof-of-the-principle experiment that uses methods of optical trapping in shaped laser beams providing cubic and quadratic potentials.
From the mere pushing to sorting of microparticles and assembly of microrobots by light
Zemánek, Pavel ; Arzola, Alejandro V. ; Brzobohatý, Oto ; Chvátal, Lukáš ; Jákl, Petr ; Kaňka, Jan ; Karásek, Vítězslav ; Šerý, Mojmír ; Šiler, Martin
We demonstrate the recent progress in the field of optical micromanipulation. We start with the classical applications of solar sail propelled by the radiation pressure and approach the recent ones dealing with optical tractor beams, optical binding and sorting of microobjects. The pioneering attempts to assemble a microrobot by light is presented.
Tractor Beam in Microworld
Brzobohatý, Oto ; Karásek, Vítězslav ; Šiler, Martin ; Chvátal, Lukáš ; Čižmár, Tomáš ; Zemánek, Pavel
Recent theoretical studies demonstrate that micro-particles can be pulled by laser beam against propagation axis even without optical gradient force. Here, we present such a tractor beam, and experimentally demonstrate its functionality.
Raman tweezers: principle and applications
Bernatová, Silvie ; Samek, Ota ; Pilát, Zdeněk ; Ježek, Jan ; Kaňka, Jan ; Šiler, Martin ; Zemánek, Pavel
Raman tweezers combines the optical trap for non-contact micromanipulation of micro-objects with Raman spectroscopy for chemical analysis of the sample. This combination presents an efficient tool for concurrent spectroscopic analysis of chemical composition and micromanipulation allowing sorting or probing of mechanical properties of the sample. Raman tweezers were successfully used for example in characterization of biomolecules like DNA, for sorting of cells and investigation of the link between their chemical and mechanical properties.
Optical rotation and manipulation with nonspherical microobjects
Arzola, Alejandro V. ; Chvátal, Lukáš ; Šerý, Mojmír ; Jákl, Petr ; Brzobohatý, Oto ; Šiler, Martin ; Zemánek, Pavel
Manipulation with microscopic objects facilitated deeper understanding of the light-matter interaction and it also has found many unique applications in the microworld. Standard optical tweezer is probably the best known device,in which a tightly focused laser beam is used for the trapping of microobjects.Utilisation of the spatial light modulator for shaping the optical intensity distribution within the trapping beam enables optimisation of the force interaction with respect to the particle shape, size or number.
Classical and advanced methods of optical micromanipulations and their applications
Zemánek, Pavel ; Brzobohatý, Oto ; Šiler, Martin ; Karásek, Vítězslav ; Samek, Ota ; Jákl, Petr ; Šerý, Mojmír ; Ježek, Jan
Optical micro-manipulation techniques have been using for more than 30 years to transfer the momentum from light to microparticles or nanoparticles and influence their movement in liquid, on the surface, or in the air. These days such techniques become more developed and frequently used in physics, chemistry and biology to manipulate, trap, rotate, or sort various types of objects, including living cells in a contactless and gentle way.
Optically bound matter
Karásek, Vítězslav ; Brzobohatý, Oto ; Šiler, Martin ; Chvátal, Lukáš ; Trojek, Jan ; Zemánek, Pavel
The interaction of laser fields with micro-objects is connected with mutual scattering between the particles and change of field momentum. The resulting very complex forces may lead to a self-arrangement of interacting particles and a creation of optically bound matter. We study this problem both theoretically and experimentally.

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