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Plane Mirrors
Published in Abdul Al-Azzawi, Light and Optics, 2018
Consider a point source of light placed a distance S in front of a plane mirror at a location O, as shown in Figure 8.2. The distance S is called the object distance. Light rays leaving the light source are incident on the mirror and reflect from the mirror. After reflection, the rays diverge, but they appear to the viewer to come from a point I located “behind” the mirror at distance S’. Point I is called the image of the object at O. The distance S’ is called the image distance. Images are formed in the same way for all optical components, including mirrors and lenses. Images are formed at the point where rays of light actually intersect at the point from which they appear to originate. Solid lines represent the light coming from an object or a real image. Dashed lines are drawn to represent the light coming from an imaginary image. Figure 8.2 shows that the rays appear to originate at I, which is behind the mirror. This is the location of the image. Images are classified as real or virtual. A real image is one in which light reflects from a mirror or passes through a lens and the image can be captured on a screen. A virtual image is one in which the light does not really pass through a mirror or lens but appears either behind the mirror or in front of the lens. The virtual image cannot be displayed on a screen.
Understanding Optics
Published in Barat Ken, Laser Safety Tools and Training, 2017
Even though the rays are traveling in the same direction, they strike the first surface at different incidence angles because that surface is curved. The ray in the center enters the lens at normal incidence, and therefore it does not bend at all. The rays farther from the center enter at larger angles the farther they are from the center and therefore bend more. At the flat surface of the lens, the rays bend again when they go from the glass back into air. As a result of these two refractions, the rays that come from the point source traveling in the same direction converge after passing through the lens. In fact, they converge in just such a way that they intersect at a single point called the focal point of the lens. The distance from the lens to the focal point is called the focal length of the lens.
Plane Mirrors
Published in Abdul Al-Azzawi, Photonics, 2017
Consider a point source of light placed a distance S in front of a plane mirror at a location O, as shown in Figure 8.2. The distance S is called the object distance. Light rays leaving the light source are incident on the mirror and reflect from the mirror. After reflection, the rays diverge, but they appear to the viewer to come from a point I located “behind” the mirror at distance S’ Point I is called the image of the object at O. The distance S’ is called the image distance. Images are formed in the same way for all optical components, including mirrors and lenses. Images are formed at the point where rays of light actually intersect at the point from which they appear to originate. Solid lines represent the light coming from an object or a real image. Dashed lines are drawn to represent the light coming from an imaginary image. Figure 8.2 shows that the rays appear to originate at I,which is behind the mirror. This is the location of the image. Images are classified as real or virtual. A real image is one in which light reflects from a mirror or passes through a lens and the image can be captured on a screen. A virtual image is one in which the light does not really pass through a mirror or lens but appears either behind the mirror or in front of the lens. The virtual image cannot be displayed on a screen.
Recent developments in hot embossing – a review
Published in Materials and Manufacturing Processes, 2021
Swarup S. Deshmukh, Arjyajyoti Goswami
For optical applications like micro-lenses, Fresnel lenses, light-guided plates, etc.; transparency is a critical property. In a semi-crystalline polymer, transparency decreases due to the crystalline part, as it causes greater refraction compared to an amorphous polymer. Such amorphous polymers like polymethyl methacrylate, polycarbonate, etc. are most suitable for optical applications as compared to the semi-crystalline polymers. Semi-crystalline polymers are highly chemically resistant, which makes them ideal for the manufacturing of microfluidic devices for medical as well as chemical applications. Due to high chemical resistance in case, if the polymer remains in the micro-cavities (forming the patterns) on the mold, it is complicated to clean it by chemical cleaning, and this mold may not be reused; to address this mold coating and set of operating parameters at an optimal level is necessary.
Liquid crystal Pancharatnam-Berry phase lens with spatially separated focuses
Published in Liquid Crystals, 2019
Yaqin Zhou, Yue Yin, Yide Yuan, Tiegang Lin, Huihui Huang, Lishuang Yao, Xiaoqian Wang, Alwin M. W. Tam, Fan Fan, Shuangchun Wen
Lens, as one of the most important and widely used optical elements, is playing an irreplaceable role in our daily life, such as the eyeglass for correcting myopia and hyperopia, camera lens for photographing, and the microscope and telescope for observing the tiniest small and furthest distance materials and structures. Comparing with the fast-developing electronics area [1], the development of optics area is rather slow. We are still using almost the same lenses comparing with those used in Newton’s time. The commonly used lenses for cameras, eyeglasses and other applications are formed by glass or plastic with curved surfaces [2,3]. With the spatial variation of thickness, the optical path difference is generated for modulating the optical-phase profile [4,5]. Due to the relatively large thickness for the lenses, the formed optical systems are normally bulky and heavy [6], which are not well suitable for the increasing demanding for the integration and miniaturisation of modern optical systems [7].
Experimental investigation of a box-type solar cooker incorporated with Fresnel lens magnifier
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Gulsavin Guruprasad Engoor, S. Shanmugam, AR. Veerappan
The focal length of the lens may be defined as the distance from the lens to the point where the incoming input beam of light converges. It is mainly represented by the simple lens equation