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Transitional motion analysis of the optically trapped particle in under-damped regime
Sűsserová, Martina ; Damková, Jana (referee) ; Harabiš, Vratislav (advisor)
The bachelor thesis deals with the analysis of the movement of optically trapped nanoparticles at low pressures and familiarizes with methods commonly used in these conditions. The practical part of this work was done in Matlab, where the undesirable signal interference was filtered out from the original data and their influence on the phase portraits of the acquired transients was analyzed. Furthermore, the damped oscillator parameters are obtained from the records of average trajectories and the distribution of position data during the transient compared with distribution of position data at stationary state by histograms.
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Transitional motion analysis of the optically trapped particle in under-damped regime
Sűsserová, Martina ; Damková, Jana (referee) ; Harabiš, Vratislav (advisor)
This bachelor thesis deals with the analysis of the transition phenomenon, which occurs when the nanoparticles enter the laser beam. Thereafter the particle is anchored around the point of focus of this beam. The main objectives of the thesis were to illustrate the dependence of the trajectory positions in relation to its instantaneous values and to obtain the parameters of the attenuated harmonic oscillator whose character is characteristic for the particle inserting the beam. Another objective of the thesis was to apply frequency filters to signal data and to observe their effects on phase diagrams and also to visualize the behavior of the particle in the vicinity of the focus in the stationary state.
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Transitional motion analysis of the optically trapped particle in under-damped regime
Sűsserová, Martina ; Damková, Jana (referee) ; Harabiš, Vratislav (advisor)
The bachelor thesis deals with the analysis of the movement of optically trapped nanoparticles at low pressures and familiarizes with methods commonly used in these conditions. The practical part of this work was done in Matlab, where the undesirable signal interference was filtered out from the original data and their influence on the phase portraits of the acquired transients was analyzed. Furthermore, the damped oscillator parameters are obtained from the records of average trajectories and the distribution of position data during the transient compared with distribution of position data at stationary state by histograms.
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Optical binding of polystyrene particles in tractor beam
Damková, Jana ; Chvátal, Lukáš ; Oulehla, Jindřich ; Ježek, Jan ; Brzobohatý, Oto ; Zemánek, Pavel
The motion of a particle illuminated by a laser beam is usually driven by the photon flow due\nto the radiation pressure and therefore for particle trapping, one has to employ gradient forces. But in a tractor beam, objects are illuminated by the uniform light intensity and even so they can be pulled against the beam propagation. There have been developed several techniques how to create such a tractor beam. In our case, the tractor beam is created by two identical Gaussian beams that interfere under the defined angle. It creates the\nstanding wave, where in the transversal plane the particle is trapped by means of the gradient\nforce, but in the total beam propagation direction, the particle manipulation is driven by the non-conservative force. It is remarkable that this force can for the specific combinations of\nparameters pull the micro-particle against the beam propagation. This kind of behavior is\nbecause of the particle scattering where the majority of the incident photons is scattered in the forward direction and, based on the principle of action and reaction, the transfer of\nmomentum leads to a backward movement of the object. The pushing and pulling force is\nsensitive to the polarization of the laser beam, its incident angle and the particle size so this\ntechnique can be used for example for sorting of objects of different sizes.
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Transitional motion analysis of the optically trapped particle in under-damped regime
Sűsserová, Martina ; Damková, Jana (referee) ; Harabiš, Vratislav (advisor)
This bachelor thesis deals with the analysis of the transition phenomenon, which occurs when the nanoparticles enter the laser beam. Thereafter the particle is anchored around the point of focus of this beam. The main objectives of the thesis were to illustrate the dependence of the trajectory positions in relation to its instantaneous values and to obtain the parameters of the attenuated harmonic oscillator whose character is characteristic for the particle inserting the beam. Another objective of the thesis was to apply frequency filters to signal data and to observe their effects on phase diagrams and also to visualize the behavior of the particle in the vicinity of the focus in the stationary state.
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