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Showing 1 to 19 of 19 for “"microlens"”.
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Theoretical and experimental assessment of the optical response of planar microlens arrays
… and response of a homogenous, apposition microlens array. While other similar studies of microlens arrays have been performed, none were found to determine the total field of view, overlap in the field of view nor the estimated maximum resolution when using a broadband illumination source …
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2D and 3D periodic templates through holographic interference lithography : photonic and phononic crystals and biomimetic microlens arrays
In this thesis a simple technique for controlling structure via holographic interference lithography was established and implemented. Access to various space groups including such important structures as the level set approximations to the Diamond, the Schwartz P structure, the FCC, and the non …
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Laser assisted nano-optics processing in optical data storage
… diffraction. Two optical lithography techniques, microlens array laser patterning and near-field scanning optical lithography, are presented to show their capabilities in nanostructures fabrication. Laser irradiation through microlens array is used to create nanostructures on phase-change films …
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Tunable Liquid Crystal Photonic Devices
… range from 0.6 m to infinity is achieved. Microlens array is an attractive device for optical communications and projection displays. In Chap. 5, we describe a LC microlens array whose focal length can be switched from positive to negative or vise versa by the applied voltage. The top …
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Operando fibre Raman sensors for Li-ion battery chemistry
… a protocol for evaluating various fibre and microlens combinations, which can be used to optimise the excitation and collection for any sample. This thesis confirms that adding a microlens enhances the Raman scattering collected by a hollow core fibre. However, challenges remain, particularly …
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Light field applications to 3-dimensional surface imaging
… of the wavefront impinging on a lens, or using microlens arrays and patterned sinusoidal masks to modulate the rays reaching a camera, both the spatial distribution and directionality of light may be captured to produce light fields. Simple depth estimation algorithms using stereo and focus …
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Analysis of Fabry-Pérot laser resonators stabilized by microlenses and applications in speckle-free imaging
… macroscopic Fabry-Pérot resonators with microlens arrays. The cavity parameters are tunable to either force fundamental-mode lasing across the array or to promote oscillation of various higher-order transverse modes. The fundamental mode produced by this resonator very closely matches …
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Stimulated emission from biological materials and novel optical resonators for diagnostic and imaging applications
… in-line holography. Finally, we construct a microlens-stabilized microlaser array, based on a titanium doped sapphire crystal, which enables speckle-free pulsed laser imaging of biological specimens with nanosecond temporal resolution.
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Photoacoustic Microscopy and Photoacoustic Computed Tomography Using High-frequency Linear Array Ultrasonic Transducers
… 1D multifocal OR-PAM system based on a 1D microlens array that provides multiple foci as well as an ultrasonic transducer array that receives the excited photoacoustic waves from all foci simultaneously. Using a customized microprism to reflect the incident laser beam to the microlens …
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Porous silicon as a platform for gradient refractive index photonics
… applicability, as well as cylindrical GRIN microlens arrays that could be useful for integration with detector pixels or light-sheet microscopes. Finally, work was conducted on utilizing PSi templates to create visibly transparent GRIN photonic elements. This concept is demonstrated by a …
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High-Speed Photoacoustic Microscopy In Vivo
… Furthermore, multiple optical foci with a microlens array have been used to provide finer than 10-micron lateral resolution--enabling the system to image capillary-level microvessels in vivo--while offering a speed potentially 20 times faster than previously existing single-focus OR-PAM. …
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Daylighting applications of micro-textured optical surfaces
… micro-textured surface to be examined is the microlens. Three systems are investigated: - A controlled diffuser incorporating cylindrical lenses to improve the distribution of the daylight. - An afocal pair of lenses to improve the penetration of daylight through beam-steering. - An angular …
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Advances in volumetric super-resolution microscopy and single-particle tracking
… (SMLFM) is a novel 3D-SMLM approach that uses a microlens array in the back focal plane of an optical microscope to capture fluorescence from multiple perspectives. Conceptually, SMLFM improves the density limit of SMLM through three key factors: 1. The PSF footprint resembles a simple and …
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High Capacity VCSEL Array Based Optical Wireless Links
… OWC transmitter is proposed and designed. A microlens array homogeniser is the first time employed in OWC to generate the uniform optical power distribution in each atto-cell and to minimise the interference between adjacent cells. Each VCSEL generates >80% beam uniformity across a 20 cm × 20 …
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Monolithic Integration Of Dual Optical Elements On High Power Semicond
… laser. First, a 40 level refractive microlens milled using focused ion beam shows a twofold reduction of the full-width half maximum 1mm above the device, showing potential for monolithic integration of coupling optics on the wafer. We then show that differential quantum efficiency of …
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Development of an ultraprecision shaping machine for manufacturing of Stavax lens molds
The production of high-precision aspheric microlenses has become increasingly difficult due to an increase in the complexity of the profile, the decrease in the lens’ size, and the demand for tighter tolerances. Machines built to fabricate these lenses generally include several expensive components …
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Stable and unstable resonators within Fabry-Pérot optical cavities containing microlenses: laser arrays, low-coherence imaging, and fractal laser modes
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-05-01