Papers by Keyword: Optics

Abstract: In this work, Fe₃O₄ nanoparticles (NPs) were synthesized using coprecipitation method and TiO₂ NPs were synthesized using sonication method. Fe₃O₄/polyaniline and TiO₂/polyaniline nanocomposites (NCs) were synthesized using polymerization methods. The samples were characterized by X-ray diffractometer, Fourier-transform infrared spectroscopy, and ultraviolet-visible spectroscopy. The results of X-ray diffraction data analysis presented that polyaniline decreased the crystallinity of Fe₃O₄ and TiO₂ NPs. However, the crystal structure of Fe₃O₄ and TiO₂ NPs did not change, which successively formed the cubic spinel and the tetragonal anatase phases. Furthermore, the functional groups of Ti-O-Ti and Fe-O were detected in the wavenumber ranges of 620-580 cm^-1 and 410-520 cm^-1, respectively. The presence of polyaniline was also detected by the emergence of a functional group of polyaniline which also showed that there was an interaction of Fe₃O₄ and TiO₂ NPs with polyaniline. Meanwhile, the results of UV-Vis data analysis showed that the addition of polyaniline decreased the bandgap energy of Fe₃O₄ and TiO₂ NPs significantly from 2.186 to 2.174 eV and from 3.374 to 3.320 eV, respectively.

Abstract: Microscope add-on toolkits for smartphone and tablet have become more widely available in the market. Although, these are sufficient to meet the demand and requirements of standard users, e.g. educational usage, these devices, in fact, do not meet the medical and biological requirements where fluorescence imaging plays a crucial role. In this paper, we introduce our innovative design in compact fluorescence microscope for smartphone and tablet. The device enables users to take fluorescent images at several excitation wavelengths using compact sources and filters.

Abstract: We report on an ambitious project in the field of automation, applied to bound and free abrasive processing of precision and ultra-precision surfaces, with potentially far-reaching consequences. This involves two main aspects:- directly processing surfaces using industrial robots, and combining robots with Zeeko CNC polishing machines to automate operations that are currently manual. These form steps towards our ultimate vision of the Integrated Manufacturing Cell for bespoke optics rather than mass-produced, and manufacture of other precision surfaces including prosthetic joint implants. Projects such as the European Extremely Large Telescope provide a relevant case study, where significant numbers of high-value bespoke optics are required.

Abstract: On an example of poly(vinylidene fluoride - trifluorethylene) ferroelectric polymer we have shown how different optical methods can be applied for basic optical constants such as refractive index and absorption coefficient obtaining, scattering surface quality control, spectral transmission range control, examining polarization degree etc. Wide range of these methods can be applied not only to thin ferroelectric films but for other different samples.

Abstract: Reviewed the application of force actuators in the optical astronomical telescopes, and introduced the working principle, mechanical structure, performance requirements and basic components of the force actuators; then compared the advantages and disadvantages of force actuator types which commonly used in astronomical telescopes, finally, propose a outlook of the development trend of the actuator on the great telescope application requirements.

Abstract: In this paper an efficient grinding mode which is employed by the Cranfield BoX ultra precision grinding machine is discussed. The equations of workpiece surface and grinding wheel surface are proposed and the grinding motion is simulated via Matlab. The trajectory of the changing cutting region is discussed. The simulation results show that this grinding mode is suit to manufacture low slope surfaces. Generally, the workpiece surface is steeper, and the cutting range of the machine is smaller. The angle of the spindle inclination, the grinding wheel width and the cutting depth should be chose properly for different manufacturing capacity.

Abstract: Aspherical supermirrors are some of the most useful neutron-focusing optics. We aim to develop multiple aspherical supermirror devices using high-precision figured aspherical focusing supermirrors to focus neutron beams with high intensities, because multiple mirrors collect a very large beam divergence. Thin mirrors with millimetre thickness are required to minimize the absorption loss of incident neutron beams since the thickness of a mirror shadows the reflective area of other mirrors. However, it is difficult to fabricate thin mirror substrates with a form accuracy at the sub-micrometre level by conventional machining. Conventional machining deforms a substrate by machining force and spring back after machining causes figure error. Furthermore the deposition of supermirrors deforms the mirror substrate by film stress. Thus, we developed a new process of fabricating a precise millimetre-thick elliptical supermirror. This process consists of non-contact figuring by the numerically controlled local wet etching technique, the minimization of surface roughness without degrading form accuracy by low-pressure polishing with a polishing pressure less than about 7 kPa (1psi), and the ion beam sputter deposition of NiC/Ti multilayers on both sides of the mirror substrate to compensate for film stress. In this paper, we report on the fabrication results of aplano-elliptical mirror substrate with a thickness of 1 mm.

Abstract: The basic optical and electro-optical effects observed in polymer-liquid crystal composites are described. Special attention is paid to the methods of optimizing polymer-liquid crystal composites optical and electro-optical properties. Finally, the applications of polymer-liquid crystal composites optical properties are given.

Abstract: In this research, Air mist-abrasion machining method for corrective figuring of a rough isotropic quartz surface before polishing process has been proposed. By this method, not only the next polishing time decreases, but also figuring efficiency increases through the possibility of using bigger abrasive grain size. Since the restrictions of laser interferometer measuring devices, capacitor probe has been used for measuring “out of flatness” of a rough isotropic quartz surface and creating error map for corrective figuring. By the proposed Air mist-abrasion figuring method, flatness of a rough isotropic quartz surface improved from PV= 0.4μm to PV=0.1μm without any change in surface roughness value.

Abstract: We emphasize in this chapter the Sol-Gel chemistry, which has gained a large number of researchers, developing interesting and sophisticated novel synthetic methods, offering a variety of approaches to new systems preparation, overcoming many of the synthetic difficulties of the past. A strong argument for using the Sol-Gel chemistry is found in the high flexibility of the method and the large choice of commercially available “dopants” that can be incorporated in the solid matrices, that might have a specific activity or reactivity to an external signal (i.e. light, magnetic, electrical, etc). From the point of view of nanotechnology applications, Sol-Gel materials are being required for critical components embedded in systems such as industrial equipment and scientific instrumentation, imaging and display, medical applications, aerospace and defense, etc. The rapidly developing sol-gel process has been used for the preparation of materials for a wide range of fields, adapting the chemistry and the novel synthetic routes to the specific systems, in order to achieve complicated developments oriented to nanotechnology applications. Clear examples can be found on Sol-Gel optics applications.