MULTI-WAVELENGTH SPECKLE REDUCTION FOR LASER PICO-PROJECTORS USING DIFFRACTIVE OPTICS

Personal electronic devices, such as cell phones and tablets, continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. Diffusers are often rotated to achieve temporal averaging of the spatial phase pattern provided by diffuser surface. While diffusers are unable to completely eliminate speckle, they can be utilized to decrease the resultant contrast to provide a more visually acceptable image. This dissertation measures the reduction in speckle contrast achievable through the use of diffractive diffusers. A theoretical Fourier optics model is used to provide the diffuser’s stationary and in-motion performance in terms of the resultant contrast level. Contrast measurements of two diffractive diffusers are calculated theoretically and compared with experimental results. In addition, a novel binary diffuser design based on Hadamard matrices will be presented. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values were subsequently measured, showing good agreement with theory and simulated values. Monochromatic speckle contrast values of 0.40 were achieved using the Hadamard diffusers. Finally, color laser projection devices require the use of red, green, and blue laser sources; therefore, using a monochromatic diffractive diffuser may not optimal for color speckle contrast reduction. A simulation of the Hadamard diffusers is conducted to determine the optimum spacing between the two diffusers for polychromatic speckle reduction. Experimental measured results are presented using the optimal spacing of Hadamard diffusers for RGB color speckle reduction, showing 60% reduction in contrast

Polychromatic determination of spectral response of PV devices

This thesis introduces a novel spectral response (SR) measurement technique using polychromatic filters (filters with very broad spectral transmittances) to determine SR of large area PV devices. Conventionally, SR of a photovoltaic (PV) device is determined by illuminating the device under test (DUT) with a series of monochromatic beams at different wavelengths as described in the international standard IEC 60904-8, or beams of limited spectral content using narrow band pass filters or monochromator. One significant problem associated with the application of the narrow band pass filters for a large-area SR measurement is that low light intensity produced on the measurement plane particularly in certain wavelength ranges: the ultraviolet and infrared. This can produce weak signal responses from a tested PV device. In addition, the imperfection of the filter s mounting position can shift the peak wavelength of the filter s transmittance at angle of incidence greater than 10. This can cause stray light on the measurement plane. The proposed SR measurement method is called as the polychromatic SR fitting method or, in short, it is known as the polychromatic method . The advantage of this method is that higher beam intensity can be produced on the measurement plane as a result of large spectral transmittance of the polychromatic filters. This can improve the signal strength of a tested PV device. This new SR measurement method works by comparing the variations in the currents which are measured at different spectra to the currents which are calculated at the same spectral conditions using the SR model. Validations of this method for a large- and small-area SR determinations show that it is potentially feasible as a new technique for determining SR of a PV device with deviations within ±2% across the wavelength bands

ПРОФІЛАКТИКА ТА ДОПОМІЖНЕ ЛІКУВАННЯ ГОСТРИХ РЕСПІРАТОРНИХ ЗАХВОРЮВАНЬ ДІТЕЙ І ДОРОСЛИХ ЗА ДОПОМОГОЮ БІОПТРОН-ПАЙЛЕР-СВІТЛА

Background. The review contains brief information on new aspects of physiotherapy (photobiomodulation) using polarized light of the Bioptron device. The palette of its active biophysical components includes 12 types of poly- and monochromatic light from halogen and LED sources. Their anti-inflammatory, analgesic, reparative, immune-normalizing, antimicrobial and other efficacy have been proven experimentally and clinically. Among the main indications are also various types of pathology of the skin and mucous membranes, treatment of wounds and the consequences of injuries, optimization of rehabilitation processes and other conditions subject to physiotherapy treatment. Materials and methods. Results. Additional specific therapeutic possibilities arise due to the creation of monochromatic (quasilaser) ranges, light modifications with fullerene with toroidal polarization and an extended range with the addition of near-ultraviolet light. PILER-light acts both locally on cells and photosensitive molecules, normalizing the electromagnetic balance in them, and systemically through influence on blood structures and acupuncture points. The bactericidal and antiviral efficacy of BIOPTRON light has been experimentally proven. During the cold season, non-invasive prophylaxis and treatment of colds with the help of BIOPTRON light therapy is essential to reduce negative manifestations without pharmacological burden on the body. The protocols for the prevention and treatment of acute respiratory diseases have been tested. Among personal protective equipment, it is advisable to reduce the light load and create mechanical obstacles to protect the eyes by using glasses with fullerene Alters. Conclusions. The main feature of ZEPTER technologies as a whole is their health-saving essence, realized through multilevel antioxidant protection. All this is a necessary component of the measures used in case of acute respiratory diseases.Обзор содержит краткие сведения о новых аспектах физиотерапии (фотобиомодуляции) с применением поляризованного света аппарата БИОПТРОН. Палитра его активных биофизического факторов насчитывает 12 видов поли- и монохроматического света от галогенных и светодиодных источников. Их противовоспалительная, противоболевая, репаратив-ная, иммунонормализующая, антимикробная и другие эффективности доказаны экспериментально и клинически. Среди основных показаний также различные виды патологии кожи и слизистых оболочек, лечение ран и последствий травм, оптимизация реабилитационных процессов и другие состояния, подлежащие физиотерапевтическом лечению. Дополнительные спеЦифические терапевтические возможности возникают за счет создания монохроматических (лазероподобных) диапазонов, модификаций света фуллереном с тороидальной поляризацией и расширенный диапазон с добавлением ближнего ультрафиолетового света. ПАИЛЕР-свет воздействует как местно на клетки и светочувствительные молекулы, нормализуя в них электромагнитный баланс, так и системно через воздействие на структуры крови и точки акупунктуры. Экспериментально доказана бактерицидная и противовирусная эффективность БИОПРОН-света. Во время холодного сезона бесконтактная неинвазивная профилактика и лечение простудных заболеваний с применением БИОПТРОН-све-тотерапии является существенной для уменьшения негативных проявлений без фармакологической нагрузки на организм. Приведены апробированные протокольные схемы профилактики и лечения острых респираторных заболеваний. Среди средств индивидуальной защиты целесообразно уменьшение световой нагрузки и создание механических препятствий для защиты глаз путем применения очков с фуллереновыми фильтрами. Главной особенностью ЦЕПТЕР-технологий в целом является их здоровье-сберегающая сущность, реализованная через многоуровневую антиоксидантную защиту. Все это является необходимым компонентом мероприятий, применяемых при острых респираторных заболеваниях.Огляд містить короткі відомості про нові аспекти фізіотерапії (фотобіомодуляції) із застосуванням поляризованого світла апарату БІОПТРОН. Палітра активних біофізичних чинників налічує 12 полі- та монохроматичних видів світла від галогенних і світлодіодних джерел. Їхня протизапальна, протибольова, репаративна та імунонормалізуюча ефективність доведена експериментально та клінічно. Серед основних показів є також різноманітні види патології шкіри та слизових оболонок, лікування ран і наслідків травм, оптимізація реабілітаційних процесів та інші стани, що підлягають фізіотерапевтичному лікуванню. Додаткові специфічні терапевтичні можливості виникають за рахунок створення монохроматичних (лазероподіб-них) діапазонів, модифікації світла фуллереном із тороїдною поляризацією та розширений діапазон із додаванням ближнього ультрафіолетового світла. ПАИЛЕР-світло впливає як місцево на клітини та світлочутливі молекули, нормалізуючи в них електромагнітний баланс, так і системно через дію на структури крові та точки акупунктури. Експериментально доведено бактерицидну та противірусну ефективність БІОПТРОН-світла. Під час холодного сезону безконтактна неінвазивна профілактика та лікування застудних захворювань із застосуванням БІОПТРОН-світлотерапії є суттєвою для зменшення негативних проявів без фармакологічного навантаження на організм. Наведено апробовані протокольні схеми профілактики та лікування гострих респіраторних захворювань. Серед засобів індивідуального захисту доцільно зменшення світлового навантаження та створення механічних перепон для захисту очей шляхом застосування окулярів з фуллереновими фільтрами. Головною особливістю ЦЕПТЕР-технологій у цілому є їхня здоров'я-зберігаюча сутність, реалізована шляхом багаторівневого антиоксидантного захисту. Все це є необхідним компонентом заходів, що застосовуються при гострих респіраторних захворюваннях

X-ray computed tomography

X-ray computed tomography (CT) can reveal the internal details of objects in three dimensions non-destructively. In this Primer, we outline the basic principles of CT and describe the ways in which a CT scan can be acquired using X-ray tubes and synchrotron sources, including the different possible contrast modes that can be exploited. We explain the process of computationally reconstructing three-dimensional (3D) images from 2D radiographs and how to segment the 3D images for subsequent visualization and quantification. Whereas CT is widely used in medical and heavy industrial contexts at relatively low resolutions, here we focus on the application of higher resolution X-ray CT across science and engineering. We consider the application of X-ray CT to study subjects across the materials, metrology and manufacturing, engineering, food, biological, geological and palaeontological sciences. We examine how CT can be used to follow the structural evolution of materials in three dimensions in real time or in a time-lapse manner, for example to follow materials manufacturing or the in-service behaviour and degradation of manufactured components. Finally, we consider the potential for radiation damage and common sources of imaging artefacts, discuss reproducibility issues and consider future advances and opportunities

Astigmatism and Pseudoaccommodation in Pseudophakic Eyes

noAdvanced IOLs with circumferential zones of different power provide pseudoaccommodation. We investigated the potential for power variation with meridian, namely astigmatism, to provide pseudo-accommodation. With appropriate power and axis orientations, acceptable pseudo-accommodation can be achieved

Building a laboratory based XUV microscope

High harmonic generation (HHG) is a non-linear interaction between a driving laser pulse and a target gas. The result of this process is the generation of coherent extreme ultraviolet (XUV) and soft X-ray radiation at harmonic frequencies of the driving laser. There are several uses for this source including attosecond time resolved spectroscopy and nanoscale imaging which this thesis will focus on.The work contained within this thesis begins by investigating the development of capillary based HHG by comparison of the experimentally observed propagation of the driving laser pulse to both a linear ionisation based model and a multimode non-linearSchrodinger equation model. Manufacture, mounting and coupling into the capillary are described. A simple linear model of propagation along the capillary is compared to experimental measurements of fluorescence along the capillary showingthe presence of mode beating. The model is extended to a non linear propagation model and validated against the spatio spectral output of the capillary.The second half of the thesis takes the XUV output from a gas cell and uses it for a coherent diffractive imaging experiment (CDI). The development of the imaging setup is described before presenting the results of a preliminary CDI experiment with a binary test sample and a polychromatic beam. Accurate measurement of the XUV beam focal position was determined by recording diffraction through a binary array of apertures. Results of a CDI experiment demonstrating a resolution of better than 200 nm is shown for a polychromatic beam with an algorithm designed for a monochromatic source

Novel Approaches for Nondestructive Testing and Evaluation

Nondestructive testing and evaluation (NDT&E) is one of the most important techniques for determining the quality and safety of materials, components, devices, and structures. NDT&E technologies include ultrasonic testing (UT), magnetic particle testing (MT), magnetic flux leakage testing (MFLT), eddy current testing (ECT), radiation testing (RT), penetrant testing (PT), and visual testing (VT), and these are widely used throughout the modern industry. However, some NDT processes, such as those for cleaning specimens and removing paint, cause environmental pollution and must only be considered in limited environments (time, space, and sensor selection). Thus, NDT&E is classified as a typical 3D (dirty, dangerous, and difficult) job. In addition, NDT operators judge the presence of damage based on experience and subjective judgment, so in some cases, a flaw may not be detected during the test. Therefore, to obtain clearer test results, a means for the operator to determine flaws more easily should be provided. In addition, the test results should be organized systemically in order to identify the cause of the abnormality in the test specimen and to identify the progress of the damage quantitatively

Laser-Based Joining of Thermoplastics to Metals: Influence of Varied Ambient Conditions on Joint Performance and Microstructure

Laser-based joining of thermoplastics to metals shows a great potential for functional design especially in terms of lightweight constructions. In the joining process, the joining speed and the energy per unit length, respectively, show an influence on time-temperature profiles measured in the joining zone. The time-temperature profile affects the joining zone and consequently the joint behavior in mechanical testing. In the current investigation, the joining zone was characterized by the melting layer. Moreover, the mechanical properties of the joint by tensile shear testing and the fracture mode were investigated. Based on the results obtained, three sets of joining speeds/energies per unit length with different mechanical behaviors were selected for further investigations under varied ambient conditions. Thereby, the influence of outdoor weathering as well as aging above the glass transition temperature of the plastic part on the joint’s performance was compared with the nonaged joints