This article focuses on the sensitivity of encapsulated interferometric probes. These probes are used mainly for BioMed and security applications. Fiber-optic sensors are interesting for these applications, as they ar...
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ISBN:
(纸本)9781510613454;9781510613447
This article focuses on the sensitivity of encapsulated interferometric probes. These probes are used mainly for BioMed and security applications. Fiber-optic sensors are interesting for these applications, as they are resistant to electromagnetic interference (EMI) and that also do not affect the surrounding medical and security equipment. Using a loop of the optical fiber with is not a suitable for these measurements. The optical fiber should be fixed to one position, and should not significantly bend. For these reasons, the optical fiber is encapsulated. Furthermore, it is necessary that the encapsulated measuring probes were flexible, inert, water resistant and not toxic. Fiber-optic sensors shouldn't be magnetically active, so they can be used for example, in magnetic resonance environments (MR). Probes meeting these requirements can be widely used in health care and security applications. Encapsulation of interferometric measuring arm brings changes in susceptibility of measurements in comparison with the optical fiber without encapsulation. To evaluate the properties of the encapsulated probes, series of probes made from different materials for encapsulation was generated, using two types of optical fibers with various degrees of protection. Comparison of the sensitivity of different encapsulated probes was performed using a series of measurements at various frequencies. The measurement results are statistically compared in the article and commented. Given the desired properties polydimethylsiloxane (PDMS) polymer has been proven the most interesting encapsulating material for further research.
Authors of this article focused on the utilization of fiber optic sensors based on interferometric measurements for securing entrance areas of buildings such as windows and doors. We described the implementation of th...
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ISBN:
(纸本)9781510613454;9781510613447
Authors of this article focused on the utilization of fiber optic sensors based on interferometric measurements for securing entrance areas of buildings such as windows and doors. We described the implementation of the fiber-optic interferometer (type Mach-Zehnder) into the window frame or door, sensor sensitivity, analysis of the background noise and methods of signal evaluation. The advantage of presented solution is the use of standard telecommunication fiber standard G.652. D, high sensitivity, immunity of sensor to electromagnetic interference (EMI) and passivity of the sensor regarding power supply. Authors implemented the Graphical User Interface (GUI) which offers the possibility of remote monitoring presented sensing solution.
Spectral investigations in the UV-VIS range of selected Al, Cu, and Fe alloys and composite materials were performed using LIBS technique. The investigated objects were typical rifle cartridges, mortars, rocket launch...
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ISBN:
(纸本)9781510613454;9781510613447
Spectral investigations in the UV-VIS range of selected Al, Cu, and Fe alloys and composite materials were performed using LIBS technique. The investigated objects were typical rifle cartridges, mortars, rocket launchers and samples of different type steel, Cu and Al alloys, as well as composite materials of special chemical composition. Two Nd:YAG lasers were applied: a short 4 ns, 60 mJ Brio Quantel/BigSky laser (1064 nm) and a long pulse 200/400 (up to 1000) mu s (similar to 2/4 up to 10 J) laser (1064 nm) constructed at the Institute of Optoelectronics MUT. This spectrochemical analysis was possible for Al, Cu, and Fe alloys objects for both lasers, and in case of composites only if the samples were irradiated by short laser pulse since in the experiment with the long pulse, all composite materials spectra, in general, were very similar to each other - they imitated a grey/black body spectra. For metal alloys in experiments with a short laser pulse only atomic spectra were observed while for long microsecond laser pulses molecular transitions have been registered for Al alloys. Electron temperatures of plasma created on different materials for short and long laser pulses were found on the base of Boltzmann plots. Temperatures are clearly higher for plasmas generated with a short laser pulse which results from much higher laser power density on the sample surface for short pulse and not from fluence which is 20-40 times larger for long pulse.
The work reported outlines the synthesis, film formation and application of NIR-absorbing metal dithiolene and metal diimine molecules suitable for film formation with varying ligands and central metals. Formation of ...
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ISBN:
(纸本)9781510603936
The work reported outlines the synthesis, film formation and application of NIR-absorbing metal dithiolene and metal diimine molecules suitable for film formation with varying ligands and central metals. Formation of an electroactive film on conducting glass or mesoporous TiO2 support can be achieved through electropolymerisation, electrodeposition, spin/drop coating or chemical attachment. In this context, we will outline the synthesis, characterisation and properties of a new family of NIR-absorbing aromatic metal diimine complexes. These complexes are shown to give rise to planar, delocalised structures with small HOMO-LUMO gaps, through the use of extended non-innocent ligands o-semibenzoquinonediimines. Herein we report the synthesis of a series of metal diimine complexes, modified to extend the electronic conjugation and shift the intense low-energy absorption from the visible to the NIR region. This study extends the range of available NIR absorping metal-complex chromophores and opens up new possibilities for wavelength tuning and application.
The paper describes the use of fiber-optic interferometer as a security sensor, which was built in a prototype of a plastic window. Its primary function is detecting the vibration and acoustic impulses, which affect t...
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ISBN:
(纸本)9781510603936
The paper describes the use of fiber-optic interferometer as a security sensor, which was built in a prototype of a plastic window. Its primary function is detecting the vibration and acoustic impulses, which affect the transparent glass part of the window prototype. The presented results are focused on the analysis of the frequency characteristic of the created prototype to verify of the sensitivity of the sensor. The knowledge of the frequency characteristic of the proposed window sensor is necessary due to the correct interpretation of the measured data. The interferometer is a Mach-Zehnder type and operates with an optical fibers G.652.D. As a radiation source, we used DFB laser with the wavelength of 1550 nm. The input optical power is 1 mW. optical signal was detected by PbSe photodetector. The generator of the harmonic signal with fixed amplitude of the signal and digital sound level meter were used to the analysis of the frequency characteristic of the prototype. The analyzed frequency spectrum was in a range of 35 Hz to 8 kHz. The paper showed that this system is suitable for measurements of vibration impulses and acoustic waves in the audible range from 40 Hz up to 3 kHz.
Fiber-optic sensors are one of the dynamically developing areas of photonics and photonic applications. This group of sensors can also include fiber-optic interferometers which enable very sensitive sensing. They are ...
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ISBN:
(纸本)9781510603936
Fiber-optic sensors are one of the dynamically developing areas of photonics and photonic applications. This group of sensors can also include fiber-optic interferometers which enable very sensitive sensing. They are entirely passive regarding power supply, and immune to electromagnetic interference. This type of sensor is dependent on the phase change. It mostly used in the field which requires high measurement accuracy. We can achieve a change of sensitivity in the order of 10-8. The fundamental problem of fiber-optic interferometry is a design and imposition (encapsulation) of the measuring arm and reference arm of the interferometer. Polydimethylsiloxane elastomer (PDMS) is one of the possibilities to encapsulation of the sensory arm. Two-component PDMS Sylgard 184 is used type. The article analyzes the effect of encapsulation into a PDMS of the measuring arm of the interferometer to frequency response and sensitivity of the Mach-Zehnder interferometer with the division of power in a ratio of 1: 1 (measuring arm and reference arm). Input power set to a reference value of 1 mW, this value was constant for all performed experimental measurements. The generator of a harmonic signal with fixed amplitude signal used for analysis of the frequency characteristic of the interferometer. The application written in LabView development environment, evaluated the amplitude-frequency spectra of the signal. Repeated test of assembled prototype verified the measured results.
The aim of this work was to learn how the influence of various solvents correlates with nonlinear optical properties of metallophthalocyanines (MPcs). The method, which was used to measure nonlinear optical properties...
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ISBN:
(纸本)9781628418620
The aim of this work was to learn how the influence of various solvents correlates with nonlinear optical properties of metallophthalocyanines (MPcs). The method, which was used to measure nonlinear optical properties, was degenerate four wave mixing (DFWM). We used ethanol, chloroform and dimethyl sulfoxide as solvent of metallophthalocyanines. The absorption spectra of MPcs solutions present a narrow Q-band in the visible region and a relatively wide B-band in the near ultraviolet. In all cases we observed the solvatochromism effect. Nonlinear optical properties of MPcs solutions change with using different polarity of solvent in the following way: n(2) ((ZnPc)) < n(2 (CoPc)) < n(2 (CuPc)).
In this paper we report the synthesis of side chain methacrylic polymers functionalized with styrylquinoline fragments. The polymerization was carried out in dimethylformamide with azobisisobutyronitrile as initiator....
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ISBN:
(纸本)9781628418620
In this paper we report the synthesis of side chain methacrylic polymers functionalized with styrylquinoline fragments. The polymerization was carried out in dimethylformamide with azobisisobutyronitrile as initiator. The products of polymerization were characterized by H-1 NMR, DSC. A study on the energetics of modelling compounds has been performed by a synergetic use of both electrochemical and optical techniques. The results of photochemical activities of the corresponding polymers are presented.
CILAS, subsidiary of Airbus Defense and Space, develops, manufactures and sells laser-based optronics equipment for defense and homeland security applications. Part of its activity is related to active systems for thr...
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ISBN:
(纸本)9781628418620
CILAS, subsidiary of Airbus Defense and Space, develops, manufactures and sells laser-based optronics equipment for defense and homeland security applications. Part of its activity is related to active systems for threat detection, recognition and identification. Active surveillance and active imaging systems are often required to achieve identification capacity in case for long range observation in adverse conditions. In order to ease the deployment of active imaging systems often complex and expensive, CILAS suggests a new concept. It consists on the association of two apparatus working together. On one side, a patented versatile laser platform enables high peak power laser illumination for long range observation. On the other side, a small camera add-on works as a fast optical switch to select photons with specific time of flight only. The association of the versatile illumination platform and the fast optical switch presents itself as an independent body, so called "flash module", giving to virtually any passive observation systems gated active imaging capacity in NIR and SWIR.
We propose a new approach, based on optical atomic magnetometers and magnetic induction tomography (MIT), for remote and non-invasive detection of conductive targets. Atomic magnetometers overcome the main limitations...
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ISBN:
(纸本)9781628418620
We propose a new approach, based on optical atomic magnetometers and magnetic induction tomography (MIT), for remote and non-invasive detection of conductive targets. Atomic magnetometers overcome the main limitations of conventional MIT instrumentation, in particular their poor low-frequency sensitivity, their large size and their limited scalability. Moreover, atomic magnetometers have been proven to reach extremely high sensitivities, with an improvement of up to 7 orders of magnitude in the 50 MHz to DC band, with respect to a standard pick-up coil of the same size. In the present scheme, an oscillating magnetic field induces eddy currents in a conductive target and laser-pumped atomic magnetometers, either stand-alone or in an array, detect the response of the objects. A phase-sensitive detection scheme rejects the background, allowing remote detection of the secondary field and, thus, mapping of objects, hidden in cargos, underwater or underground. The potential for extreme sensitivity, miniaturization, dynamic range and array operation paves the way to a new generation of non-invasive, active detectors for surveillance, as well as for real-time cargo screening.
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