Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"optical traps"”.
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Methods of single-molecule energy landscape reconstruction with optical traps
Optical traps facilitate measurement of force and position as single molecules of DNA, RNA, or protein are unfolded and refolded. The effective energy landscape of a biomolecule can be reconstructed from the force and position data, providing insight into its structure and regulatory functions. We …
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Engineering optical traps for new environments and applications in the measurement of biological adhesives and motors
Optical traps have played a central role in the exploration of biological systems through the examination of molecular motors, biopolymers, and many other interactions at the nano and micro length scales. This thesis seeks to extend the applications of optical trapping instrumentation and the …
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Peeking and poking at a new quantum fluid : studies of gaseous Bose-Einstein condensates in magnetic and optical traps
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 2000.
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Creation of an all-optical Bose-Einstein condensate
… of 87Rb atoms, with the creation of a large all-optically cooled Bose-Einstein condensate as a proof of the temperatures and densities achieved. In most cold atoms experiments, the Bose-Einstein condensate is achieved by evaporating the atoms in a magnetic trap.;Due to the swallowness of magnetic …
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Design of a dual beam optical trap
Dual beam optical traps use radiation pressure from two counterpropagating laser beams to manipulate microscopic particles. Typical traps use optical fibers to guide those beams. This thesis proposes a design for the coaxial alignment of optical fibers that allows for the fibers to translate along …
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Magic Trapping of a Three-Level System for Rydberg Quantum Computation
… blockade mechanism, which stores qubits in optically trapped neutral atoms. A detailed theory for these optical traps is presented. While the traps are essential, they induce decoherence in the atoms they trap. We propose a method of "magic" trapping by which this decoherence may be …
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Development of a heating stage for an optical trapping microscope
… of biological systems through research using optical tweezers. Currently, experiments involving force and position manipulations of cellular molecules take place at room temperature. Experiments with these molecules have the potential to yield more information about biological systems were …
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Measuring acoustic fields in an optical trap
This thesis describes progress in the use of optical traps for measurement of acoustic fields, a first step toward acoustic micromanipulation in fluids. The optical trap used throughout this study is carefully characterized. Eccentricity of measured distributions of thermal fluctuations of trapped …
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Inverse techniques: problems in optics and gas sensing
… the algorithm than the choice of forward model. Optical tweezers trap and manipulate particles with light beams. In order to manipulate the particles in a desired way it is necessary for the shape and position of the light beam to be controlled. One way of achieving a desired light beam is to use …
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Optical Deformation of Emulsion Droplets
Optical tweezers are a useful and fascinating tool for the manipulation of a range of microscopic particles. I describe the set up of optical trapping apparatus, and investigate the use of a spatial light modulator for the creation of arrays of optical traps. Optical deformation of microemulsion …
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Spectroscopy of Ultracold LiRb Molecules Using Ionization Detection
… trapping Li and Rb atoms in overlapping magneto-optical traps (MOTs) and using light resonant with a free-bound transition to create weakly bound excited state molecules in a process known as photoassociation (PA). We explore weakly bound vibrational levels of LiRb with PA spectroscopy using …
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Nonlinear optical emission and near-field enhancement effects in arrays of gold bowtie nano-antennas
… we focus on laser-induced damage, nonlinear optical emission, and a proof-of-concept for utilizing arrays of gold BNAs to enhance the forces in an optical trapping system. From FDTD simulations, the optical response of a single BNA is demonstrated to increase the local intensity by a factor …
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Enhanced transport through confined channels by stationary and fluctuating potentials
… channels and colloidal particles. Holographic optical tweezers are used to modulate the potential energy landscape in those channels. We show how to extract the underlying energy potential by analysing local transition probabilities. Our method is applicable both to equilibrium systems and …
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Semiconducting Devices and Nanomaterials: Insight from Computational Chemistry
… dot surface and tie these features to the optical properties of the quantum dot. We find that undercoordinated surface atoms on the surface of CdSe can cause optical traps even when there are no traps in the ground state band structure, show that surface reorganization and annealing can …
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Hybrid optical and acoustic trapping
… for a number<br/>of different applications. Optical tweezers, a technique which uses highly focused laser beams to trap and move microscopic objects, has become an important tool for many applications owing to its incredible precision and dexterity. Optical trapping is, however, limited in …
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Light-induced many-body correlations in ultracold gases
… in ultracold gases using light. A high-finesse optical cavity is used to enhance the atom-light interaction and we can produce a variety of entangled states which can overcome the standard quantum limit. The quantum correlations are generated by sending very weak light into the cavity which …
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Fresnel-focusing and bessel-beam integrated optical phased arrays for optical trapping applications
Optical trapping and tweezing - the manipulation of particles using optical forces - enables direct interaction with biological samples and non-invasive monitoring of their properties. As such, optical trapping has become a common tool in biology with applications ranging from better understanding …
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Study of Ultracold Fermi Gases in the BCS-BEC Crossover: Quantum Monte Carlo Methods, Hydrodynamics and Local Density Approximation.
… of ultracold Fermi gases in harmonic magneto-optical traps, starting from QMC equations of state. We study the propagation of first and second sound in ultracold Fermi gases in cylindrical geometry, using the hydrodynamic equations of superfluids.
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Modeling and Experimental Techniques to Demonstrate Nanomanipulation With Optical Tweezers
… of effective prototyping tools at the nanoscale. Optical trapping is well established for flexible three-dimensional manipulation of components at the microscale. However, it has so far not been demonstrated to confine nanoparticles, for long enough time to be useful in nanoassembly applications. …
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Dynamics and statistics of hydrodynamically interacting particles in laminar flows
… where polystyrene beads are caught by optical traps and simultaneously exposed to linear shear flows in a special microfluidic device. The results are published and further investigations are in progress.The third theme concentrates on the rheology of colloidal suspensions. Our …
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