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Fundamentals of Optical Concentration
Published in Roberto Ramirez-Iniguez, Sevia M. Idrus, Ziran Sun, Optical Wireless Communications, 2008
Roberto Ramirez-Iniguez, Sevia M. Idrus, Ziran Sun
Two other fundamental concepts widely used in the design of optical concentrators are Fermat’s principle and the optical path length. The Fermat principle states that the time required by light to travel from one point to another (in an optical system) is the minimum when compared to the time required from neighboring paths (a more accurate definition is given in Section 4.3). This is particularly relevant in GO analysis and when producing ray-tracing algorithms. The optical path length refers to the geometrical length of the path followed by light when traveling through an optical system.
The Effects of Curved Gas-Liquid Interface on Light Reflectance Liquid Film Measurement for an Optical Waveguide Film
Published in Nuclear Science and Engineering, 2023
Hajime Furuichi, Kenichi Katono, Yuki Mizushima, Toshiyuki Sanada
The measurement principle of the liquid film thickness with an OWF is based on a conventional laser technique18–20 using an optical fiber embedded in a channel wall. Figure 1 shows a schematic of the measurement principle of the optical fiber technique. The optical fiber was installed vertically on the channel wall surface, and its tip surface was adjusted to the same level as that of the channel wall surface. Light propagates in the optical path, called the fiber core, owing to total reflection. The propagating light reaches the fiber tip and is emitted from the tip. The emitted light is reflected at the surface of the liquid film, and some of the reflected light reenters the fiber core. The energy of the reentered light depends on the liquid film thickness because the spatial density of the light energy changes, and the energy of the reentered light increases when the liquid film is thinner. Therefore, the thickness of the liquid film can be measured by quantifying the reentered light.
Development of amplification system for point-of-care test of nucleic acid
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Shaolei Huang, Jiageng Wu, Haozheng Dai, Runxin Gao, Hongyu Lin, Dongxu Zhang, Shengxiang Ge
The system used optical fibers, lenses, filters, etc. to build the optical path. Different wavelengths of LED light were processed and then irradiated to the amplification chamber through the excitation fiber to excite the fluorescence used to label the amplification products during the amplification process. Finally, the fluorescence signal excited in the product was received through the receiving fiber and photodiode (PD), and then a microcontroller was used for photoelectric signal conversion to obtain the fluorescence signal value corresponding to each signal sampling. The Ct of the sample to be measured can be calculated by plotting the fluorescence curve, and the copy number can be deduced by combining with the standard fluorescence curve to reach the quantitative analysis of the unknown sample. As shown in Figure 1e, the fluorescence detection system can use up to six detection channels, enabling the excitation and reception of fluorescence at six different wavelengths, which together with the TaqMan probe method can achieve the detection of multiple pathogens in single sample (Domingo et al. 2012). In addition, a separate channel can be selected as an internal positive quality control to identify false negatives due to amplification abnormalities and ensure the accuracy of results.