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Infrared devices and techniques
Published in John P. Dakin, Robert G. W. Brown, Handbook of Optoelectronics, 2017
Antoni Rogalski, Krzysztof Chrzanowski
A monochromator is an optical instrument that uses a dispersing component (a grating or a prism) and transmits to the exit slit (optionally directly to the detector) only a selected spectral fraction of the radiation incoming to the entrance slit. The center wavelength of the transmitted spectral band can be changed within the instrument’s spectral region by rotating the dispersing element. Very good spectral resolution can be achieved using grating monochromators (as high as 0.1% of the wavelength). However, the monochromator transmits the optical radiation only in a very narrow spectral band. Moerover, grating monochromators are designed using low speed optics. As a result, the optical detectors at the output of the monochromators receive only a very small fraction of the radiation incoming to the monochromator input. Therefore, spectroradiometers built using grating monochromators suffer poor sensitivity. Cooled optical detectors of ultra-high sensitivity are often used in such spectroradiometers to reduce the aforementioned drawback, however with a limited effect.
Optical properties of relevance to nanomaterials
Published in Nils O. Petersen, Foundations for Nanoscience and Nanotechnology, 2017
Third, as the light is reflected from the glass to the air, the angle at which total reflection occurs is much less than 90o. This shows that above this angle, called the critical angle, there is always complete reflection. This is also termed total internal reflection. Total internal reflection allows light to be confined to a medium of higher refractive index, such as an optical fiber. Note that the critical angle is the same for the two polarizations and it can be calculated from the arcsin $ {\text{arcsin }} $ of the ratio of the refractive indexes θc=arcsinnt/ni=sin-1nt/ni $$ {\theta _c}~ = ~arcsin\left( {{n_t}/{n_i}} \right)~ = ~si{n^{ - 1}}\left( {{n_t}/{n_i}} \right) $$
Semiconductor Optical Fibers
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Optical Properties and Applications of Semiconductors, 2023
Lele Zang, Qixun Xia, Zhijun Du, Nanasaheb M. Shinde
With the change of times, semiconductor fibers have received great attention and developed rapidly. Initially, Kao and Hockham introduced the basic principle of the application of optical fiber in communication, and the bold idea was to use pure glass instead of copper wire to transmit signals through light [1]. Their work described the structure and material properties of insulating fibers for long-distance high-information optical communication, which opened the door to fiber optic communication, in everyday life. Optical fibers are used to transmit information over long distances because the loss of light in optical fibers is much less than the loss of electricity in wires.
ACO–OFDM with Improved Bandwidth Efficiency over Long Haul and MIMO Optical Fiber Communication Systems
Published in IETE Journal of Research, 2022
Optical fiber has been an efficient transmission channel for high speed and long haul communication link up to transoceanic distances. It holds enormous data speed capacity with low environmental interferences. Basic optical fiber set-up consists of single-mode fibers for long distance high speed links where as multimode fiber is a low cost option for short distance, slower data rate applications [1]. Optical fiber links are backbone for links between telephone exchanges, Cable TV connections and base stations to remote node terminals in radio over fiber. Recent challenges for communication industry are related to network and device designing that can sustain for upcoming advancements in technologies and demands on user end. Cloud radio access network (C-RAN) for 5G requires a fair investment in point-to-point fiber link closer to the user end [2–4].
Single event transient effects on 3T and 4T CMOS active pixel sensors for different technologies
Published in Australian Journal of Electrical and Electronics Engineering, 2019
M. A. Sukor, A. S. Hedzir, S. S. Sabri, N. F. Hasbullah
High-performance image sensors are compulsory for the space imaging mission such as satellites to capture an exact view of the real-time space phenomenon. Over the last few years, CMOS Active Pixel Sensors (APS) take precedence for high-performance image sensors as compared to Charge-coupled device (CCD) due to their good electro-optical performance, lower power consumption and tolerance to the space radiation environment (Bigas et al. 2006; Hopkinson 2000; Virmontois et al. 2012, 2017). Their compatibility with standard CMOS technology is another essential value as it allows them to be embedded on-chip (Hopkinson 2000; Pickel et al. 2003; Eid et al. 2001). CMOS APS integrates electrical function surrounding the array of pixel to dominate the advantages of CMOS technology, but it increases the vulnerability to radiation (Bigas et al. 2006).
Minreview: Recent advances in the development of gaseous and dissolved oxygen sensors
Published in Instrumentation Science & Technology, 2019
Q. Wang, Jia-Ming Zhang, Shuai Li
Electrochemical oxygen sensing in oxygen detection requires larger oxygen consumption and the response time is slow. In addition, the poor security and other issues limited the applications, but the method operates in high-temperature environments. Optical oxygen sensor arecurrently the main research direction of the combination of fluorescent materials and optical fibers. Fluorescent materials offer unique fluorescence characteristics that are only sensitive to oxygen. Optical fibers provide small size, light weight, and the absence of electromagnetic interferences. Optical oxygen sensors combine the advantages of both to achieve miniaturization, online analysis with remote sensing to provide new possibilities. However, the fluorescence signal of the optical oxygen sensor based on the fluorescent material are very weak, so the collection of fluorescence is a problem that must be solved.