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History of Beam Shaping
Published in Fred M. Dickey, Scott C. Holswade, David L. Shealy, Laser Beam Shaping Applications, 2018
Beam shaping has had a long, interesting, and controversial history, dating back to the seventh century B.C. when people used magnifying glasses to concentrate sunlight into beams which would ignite wood.1 There has been a continuing interest in using solar energy for heating, cooling, and also for the production of electricity2; solar energy promises to help meet the growing world-wide demand for more energy. Another important application of beam shaping during the past 180 years is the use of the Fresnel lens in lighthouses. Other contemporary applications of Fresnel lenses include traffic lights, wireless networks, and overhead projectors. An overview of early beam shaping is given in Section I.A.
Lenses
Published in Abdul Al-Azzawi, Photonics, 2017
A Fresnel lens replaces the curved surface of a conventional lens with a series of concentric grooves molded into the surface of a thin, lightweight glass or plastic sheet, as shown in Figure 10.15. The grooves act as individual refracting surfaces, like tiny prisms, when viewed in cross section, bending parallel rays in a very close approximation to a common focal length. Because the lens is thin, very little light is lost by absorption compared to conventional lenses. Fresnel lenses are a compromise between efficiency and image quality. High groove density allows higher quality images (as needed in projection), while low groove density yields better efficiency (as needed in light gathering applications). Fresnel lenses are most often used in light gathering applications, such as condenser systems or emitter/detector setups. Fresnel lenses can also be used as magnifiers or projection lenses.
Optofluidic devices and their applications
Published in Guangya Zhou, Chengkuo Lee, Optical MEMS, Nanophotonics, and Their Applications, 2017
Figure 14.18a shows a bulk lens where light refracts only at the surface of a bulk lens and the lens material in the middle (shown in the darker color) makes no contribution to the steering of incoming light. Thus, a bulk lens can be broken down into smaller subsections, where the curved surfaces in each section are replaced with flat surfaces of varying angles (Figure 14.18b). As a result, a Fresnel lens significantly reduces the lens material and cost, while offering a large aperture size. However, since conventional Fresnel lenses are made from solid materials (e.g., glass or plastic), their optical performance, such as a focal length, is fixed once the lens material and geometry has been designed. To provide a degree of tunability for a Fresnel lens, Park's group proposed an arrayed form of the liquid prisms where each prism is individually controlled by electrowetting to replicate the subsections of a solid Fresnel lens [84]. The set of discontinuous prisms in a Fresnel lens steers light through steep prism angles at the edges and incrementally smaller angles for intermediate prisms (see Figure 14.18c). By individually controlling each prism using electrowetting, they have achieved 3D focal control along the longitudinal (263 mm ≤ flong ≤ ∞) as well as the lateral (0 ≤ flat ≤ 30 mm) directions. The optofluidic tunable Fresnel lens presented here would become a leading technology in compact and tunable optical systems, with applications ranging from imaging and motion tracking to multicollector solar systems.
Energy and exergy based study on a box type solar cooker coupled with a Fresnel lens magnifier
Published in International Journal of Green Energy, 2023
Gulsavin Guruprasad Engoor, S. Shanmugam, A. R. Veerappan
Fresnel lenses are crucial components in the solar concentration process as they can concentrate the solar power incident on them by a hundred times to a point (Ribeiro et al. 2009). They are used extensively in solar photovoltaic (Lin 2013) and thermal systems (Lin et al. 2014). For greater clarity and magnification, the Fresnel magnifiers play a vital role. They are very light in weight and easily portable. The incorporation of Fresnel lens in solar thermal applications is a better method to enhance their thermal performance. Experiments were performed on a solar still with Fresnel lenses, and were compared with a conventional system (Mu et al. 2019). The increment in efficiency and water productivity rate of the modified solar still was 84.7% and 467.4%, respectively. Solar distillation carried out by incorporating Therminol 55–Al2O3 as heat transfer fluid, had superior production compared to the conventional solar still (Muraleedharan et al. 2019).
Investigation of effect of the Fresnel lens on the performance of the double slope single basin solar still
Published in International Journal of Ambient Energy, 2021
V. Sriram, Venkatesh Kondraganti, Charan Tejeswar Reddy Lokireddy, Jeya Jeevahan, G. Britto Joseph, R. B. Durai Raj, G. Mageshwaran
A Fresnel lens can capture more oblique light from a light source, thus allowing the light from a lighthouse equipped with one to be visible over greater distances. Fresnel lenses are usually made of glass or plastic; their size varies from large (old historical lighthouses, meter size) to medium (book-reading aids, OHP viewgraph projectors) to small. In many cases, they are very thin and flat, almost flexible, with thicknesses in the 1–5 mm (0.039–0.197 inch.) range. In this, the reading is initially taken by using contaminated water and therefore results are taken. After that the reading is taken by using industrial waste water. Two sets of reading are taken. Firstly, the readings are taken without the use of the Fresnel lens and hence its corresponding reading and graphs are made. Secondly, the readings are taken using the Fresnel lens (Figure 6).
Design and fabrication of an LED lantern based on light condensing technology
Published in Journal of International Council on Electrical Engineering, 2018
Guoming Wang, Seong-Cheol Hwang, Woo-Hyun Kim, Gyung-Suk Kil
The Fresnel lens with a focal length and a diameter of 120 mm was used for light condensing. Compared with the conventional convex and bi-convex lens, the Fresnel lens reduces the amount of material by dividing the lens into a set of concentric grooves. As a result, its thinness and weight can be reduced greatly and it is available in various sizes. The groove structure allows the parallel input light rays to be concentrated to the focus point. Based on this principle, the LED package was placed at the focal point, where was 120 mm away from the lens. Therefore, the light ray emitted from LED package can be reflected in parallel by the Fresnel lens.