56,309 research outputs found
Toward a new generation of photonic humidity sensors
This review offers new perspectives on the subject and highlights an area in need of further research. It includes an analysis of current scientific literature mainly covering the last decade and examines the trends in the development of electronic, acoustic and optical-fiber humidity sensors over this period. The major findings indicate that a new generation of sensor technology based on optical fibers is emerging. The current trends suggest that electronic humidity sensors could soon be replaced by sensors that are based on photonic structures. Recent scientific advances are expected to allow dedicated systems to avoid the relatively high price of interrogation modules that is currently a major disadvantage of fiber-based sensors
Glass and Glass–Ceramic Photonic Materials for Sensors
Recent developments in sensors are pushing for optimized materials
that can increase their usage, bolster their sensitivity and enable new and more
efficient transduction mechanisms. We hereby review some of the most relevant
applications of glasses and glass-ceramics for photonic sensors considering the
recent trends and innovative approaches. This review covers from bulk glasses
to thin films and from fiber optics to nanocrystal-based and their applications in
sensing
Silicon Photomultipliers in Particle and Nuclear Physics
Following first large-scale applications in highly granular calorimeters and
in neutrino detectors, Silicon Photomultipliers have seen a wide adoption in
accelerator-based particle and nuclear physics experiments. Today, they are
used for a wide range of different particle detector types, ranging from
calorimeters and trackers to particle identification and veto detectors, large
volume detectors for neutrino physics and timing systems. This article reviews
the current state and expected evolution of these applications, highlighting
strengths and limitation of SiPMs and the corresponding design choices in the
respective contexts. General trends and adopted technical solutions in the
applications are discussed.Comment: 17 pages, 18 figures, review paper published in Nuclear Instruments
and Methods A; v2 correcting a missing figure link in tex
Absorbance based light emitting diode optical sensors and sensing devices
The ever increasing demand for in situ monitoring of health, environment and security has created a need for reliable, miniaturised sensing devices. To achieve this,
appropriate analytical devices are required that possess operating characteristics of reliability, low power consumption, low cost, autonomous operation capability and
compatibility with wireless communications systems. The use of light emitting diodes (LEDs) as light sources is one strategy, which has been successfully applied in chemical
sensing. This paper summarises the development and advancement of LED based chemical sensors and sensing devices in terms of their configuration and application, with the focus on transmittance and reflectance absorptiometric measurements
Simultaneous Measurement for Strain and Temperature Using Fiber Bragg Gratings and Multimode Fibers
An all-fiber sensor capable of simultaneous measurement of temperature and strain is newly presented. The sensing head is formed by a fiber Bragg grating combined with a section of multimode fiber that acts as a Mach-Zehnder interferometer for temperature and strain discrimination. The strain and temperature coefficients of multimode fibers vary with the core sizes and materials. This feature can be used to improve the strain and temperature resolution by suitably choosing the multimode fiber. For a 10 pm wavelength resolution, a resolution of 9.21 μ∈ in strain and 0.26°C in temperature can be achieved
Dual refractive index and viscosity sensing using polymeric nanofibers optical structures
Porous materials have demonstrated to be ideal candidates for the creation of optical sensors with very high sensitivities. This is due both to the possibility of infiltrating the target substances into them and to their notable surface-to-volume ratio that provides a larger biosensing area. Among porous structures, polymeric nanofibers (NFs) layers fabricated by electrospinning have emerged as a very promising alternative for the creation of low-cost and easy-to-produce high performance optical sensors, for example, based on Fabry-Perot (FP) interferometers. However, the sensing performance of these polymeric NFs sensors is limited by the low refractive index contrast between the NFs porous structure and the target medium when performing in-liquid sensing experiments, which determines a very low amplitude of the FP interference fringes appearing in the spectrum. This problem has been solved with the deposition of a thin metal layer (∼ 3 nm) over the NFs sensing layer. We have successfully used these metal-coated FP NFs sensors to perform several real-time and in-flow refractive index sensing experiments. From these sensing experiments, we have also determined that the sponge-like structure of the NFs layer suffers an expansion/compression process that is dependent of the viscosity of the analyzed sample, what thus gives the possibility to perform a simultaneous dual sensing of refractive index and viscosity of a fluid
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