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Prisms
Published in Abdul Al-Azzawi, Light and Optics, 2018
Prisms are widely used in building optical devices, such as a prism spectrometer, which is commonly used to study the wavelengths emitted by a light source. Prisms are also used in building optical fibre devices, such as an opt-mechanical switch, which deflects or deviates an optical signal through a telecommunication system. Prisms can invert or rotate an image, deviate a light beam, disperse light into its component wavelengths, and separate states of polarization. The orientation of a prism (with respect to the incident light beam) determines its effect on the beam. Prisms can be designed for specific applications. The most popular prisms are right angle prisms, Brewster’s angle dispersing prisms, Penta prisms, solid glass retro-reflectors, equilateral dispersing prisms, littrow dispersion prisms, wedge prisms, roof prisms, and Dove prisms. Some of these commonly used prisms are discussed in detail in this chapter.
Prisms
Published in Abdul Al-Azzawi, Photonics, 2017
Refraction of light passing through a prism, as shown in Figure 11.14, is understood using light rays and Snell’s law. This figure shows how a single light ray that is incident on the prism from the left emerges bent away from its original direction of travel. When the ray exits the prism, the emerged ray is bent by an angle of δ,called the angle of deviation (δ). The angle of deviation will change as the angle (θ1)of the incident ray changes. The magnitude of the deviation angle also depends on the apex angle (A) of the prism, the index of refraction of the prism material, and the wavelength of the incident light. The angle of deviation reaches its minimum value when the light passing through the prism is symmetrical; i.e., when θ1 = θ2,as shown in Figure 11.14. Then, the angle is called the minimum deviation angle (δm).
Optical Signal Transduction with an Emphasis on the Application of Surface Plasmon Resonance (SPR) in Antibody Characterisation
Published in Richard O’Kennedy, Caroline Murphy, Immunoassays, 2017
Caroline Murphy, Aoife Crawley, Hannah Byrne, Kara Moran, Jenny Fitzgerald, Richard O’Kennedy
The fundamental mechanics of SPR start when polarised light is shone through a prism onto a metal surface at a certain angle and light is reflected (Fig. 11.1). At a certain angle at which the light passes through the prism, total internal reflection (TIR) occurs. Photons of light that are totally internally reflected create an evanescent wave at the interface between the gold film and the reaction medium. The evanescent wave moves exponentially and excites what are known as plasmons (electron charged density waves) at the gold surface. This excitation causes a decrease in the intensity of the reflected light. The angle at which this occurs is called the resonance angle or SPR angle. This angle is intrinsically affected by changes in the RI, which occur between the gold surface and the liquid medium. Upon accumulation of biomolecules at the gold/liquid interface, the RI changes, thus causing a shift in the SPR angle, which can be seen in Fig. 11.1A (shifting from a red to a blue line). This shift is measured, recorded, and is displayed in real-time on a sensorgram. When a biomolecular interaction occurs at the sensor surface, a change in mass occurs. These changes at the interface are directly proportional to concentrations in the picomolar to nanomolar range [25, 26]. SPR capabilities go beyond the quantitative and qualitative measurement of intermolecular reactions, and, as the shift in resonance angle can be measured over time, kinetic data can be obtained. This can be utilised to generate information relating to the affinity and specificity of the measured biomolecular interaction [25].
Design of an RGB colour separation prism based on the maximum ratio of aperture to length
Published in Journal of Modern Optics, 2023
Yunfeng Jiang, Dongsheng Wu, Bing Zhou, Jie Liu, Fuyu Huang
The effective transmission of light inside the prism requires total internal reflection. In this work, the prism material considered is glass ‘K9’ with n = 1.51630 and a total reflection angle . Figure 4 shows that the total internal reflection of the blue and red light occurs on the colour separation surfaces. and are, respectively, the half-field angles of the blue and red light determined by the total internal reflection. The green light is not restricted by this consideration. Therefore, we obtain: where,
Steering light in fiber-optic medical devices: a patent review
Published in Expert Review of Medical Devices, 2022
Merle S. Losch, Famke Kardux, Jenny Dankelman, Benno H. W. Hendriks
Another optical component that can be added outside the optical fiber to steer a light beam is a lens, as described in twelve patents [26,33,57–66]. A lens redirects a light beam due to refraction, changing its angular distribution. Lenses can be divided into converging and diverging lenses. In six devices, the distal tip includes a converging lens [26,33,57–60]. These converging lenses can be semi-spherical [57,58] or convex lenses [26,33,58–60]. In most standard designs, a converging lens focuses a light beam on a specific tissue area [26,33,57–60], see Figure 2j. The same converging lens can also collect light from this specific tissue area to one or more collecting fibers [33,57]. Smith [60] describes a special design including a converging lens and a faceted surface. The faceted surface receives light from the optical fiber and refracts it into different beam elements, which are then focused into multi-spots by a convex lens. In six devices, the distal tip includes a diverging lens [61–66]. This can be a semi-spherical [61–63], gradient-index [64], or concave [65] lens. Diverging lenses illuminate a wide area in the tissue. Nagale et al. [66] describe a special type of diverging lens, which is a triangular prism. The distal tip of this device consists solely of a prism that is directly coupled to the optical fiber. A light beam entering the prism refracts at the first face and then refracts again at the second face. As a result, light is emitted radially with a wide angular distribution. The prism can also rotate, allowing light to be emitted into the tissue in a 360° range, see Figure 2k.
Research on the passive nuclear level gauge
Published in Radiation Effects and Defects in Solids, 2019
Xi-Cheng Xie, Yuan-Yuan Zhang, Ya-Juan Guo, Wan-Chang Lai
The simulation object in the article is the commonly used electrostatic precipitator hopper in the thermal power industry and four passive nuclear level gauge. There are two main types: four prism type and quadrangular frustum pyramid type. This paper establishes a model of quadrangular frustum pyramid type hopper (Table 1), which dust flow is 50 t/h, the bottom size is 400 mm × 400 mm and 4800 mm in height. The hopper is made of typical reinforced steel structure, the outer surface of the hopper’s four side plates weld with reinforcing rib which is made of channel steel, angle steel. The reinforcing rib model is Q235A. The four passive nuclear level gauge are located on the right side of the hopper from which bottom to the top is NO.1 passive level gauge (low-level passive level gauge), NO.2 passive level gauge, NO.3 passive level gauge (high-level passive level gauge), NO.4 passive level gauge, respectively. The location height of the four passive nuclear level gauge is 90, 180, 270 and 360 cm, respectively.