Quantum cascade laser is one of the most sophisticated semiconductor devices. Its technology requires extremely high precision and layers quality. Device performance is limited by thermal extraction form laser core. One of solutions is to apply highly resistivity epitaxial material acting as insulating layer on top of the QCL. Present work describes consequent steps of elaboration of MOVPE technology of Fe-compensated InP layers for further applications in quantum cascade lasers.
The paper presents a modification of capillary optical fibers fabrication method from an assembled glass preform. A change of dimensional proportions in the capillary optical fiber drawn from a single preform is allowed on-line via the control of overpressure and thermal conditions in the outflow meniscus which essentially lowers the manufacturing costs. These conditions are among the solutions (velocity fields) of the Navier-Stokes equations adapted to the capillary optical fiber pulling geometry and temperature distribution in the oven. The velocity fields give solutions to other quantities of interest such as flow rate, pulling force and fiber geometry. The calculation and experimental results for capillary optical fibers were shown in the following dimensional range: internal diameters 2-200 µm, external diameters 30-350 µm, within the assumed dimensional stability (including ellipticity) better than 1%. The parameters of fabricated capillary optical fibers of high-quality low-loss optical multicomponent glasses were: losses 100 dB/km, mechanical strength above 1GPa with Weibull coeffcient in the range 3-7, internal numerical aperture 0.1-0.3, external numerical aperture 0.1-0.3, core index 1.5-1.8, transparency 0.4-2 µm, thermally and/or chemically conditioned internal surface, double polyimide protection layer, soft or hard jacketed, connectorized. The capillary optical fibers were applied in our own and several external laboratories in spectroscopy, refractometry, micro-fluidics and functional microoptic components. The paper summarizes a design, technological and application work on capillary optical fibers performed during a recent national research program devoted to optoelectronic components and modules.
What does it take to secure a foothold in the global high-tech market and keep such a business afloat? We can look at the experiences of other companies to find proven solutions and answers to the most important questions.
This paper comprehensively presents key issues in design of an original optoelectronic measurement device built to assess amount of suspended particulate matter. The paper is introduced with a short explanation of concerns with a suspended particulate matter, what role it has in the air quality and how it affects health of human population. Then, problems of construction of the measurement device supported by a theoretical explanation on the basis of Mie theory are discussed. Subsequently, it is followed by an analysis of the device operation both in laboratory and in real conditions. Results obtained with the presented device are compared with the professional measurement equipment and an expensive, outdoor measurement station. Paper is concluded with observations of differences in spatio-temporal PM change at very close but significantly different city locations.
New optimized 2x2 slotted array antenna is designed using HFSS to operate at 28.1 GHz, using RT6010 substrate with height of 1.6 mm, tangent loss of 0.0023 and dielectric constant of 10.2 and overall dimension of 12x12 mm2, for 5G mobile applications. The 2x2 slotted linear array antenna achieved a high gain of 18.3 dB at 28.1 GHz with 10 dB bandwidth of 1.39 GHz, and with 83.21% of size reduction.
The perovskites XBiO3 (X = Al, Ga, In) have been studied in terms of mechanical, optical and thermoelectric behavior for energy harvesting application. Density functional theory is applied to study electronic, optical and thermoelectric properties of the studied materials. Structural, mechanical and thermodynamic stabilities are confirmed from the tolerance factor, Born mechanical stability and formation energy/specific heat capacity. Poisson and Plough ratios show the studied materials are ductile and have ability to withstand pressure. Band structure analysis shows the indirect band gap 3.0/2.1/1.0 eV for ABO/GBO/IBO. A complete set of optical spectra is reported by dielectric constants, refractive index, optical conduction, absorption of light and optical loss energy. Shifting of maximum absorption band to visible region increases the potential of perovskites XBiO3. Transport characteristics are also investigated by electrical conductivity, Seebeck coefficient and figure of merit.
Optoelectronic technology plays an important role in medical diagnosis. In the paper a review of some optoelectronic sensors for invasive and non-invasive human health test is presented. The main attention is paid on their basic operation principle and medical usefulness. The paper presents also own research related to developing of tools for human breath analysis. Breath sample unit and three gaseous biomarkers analyzer employing laser absorption spectroscopy designed for clinical diagnostics were described. The analyzer is equipped with sensors for CO, CH4 and NO detection. The sensors operate using multi-pass spectroscopy with wavelength modulation method (MUPASS-WMS) and cavity enhanced spectroscopy (CEAS).
Transparent Conductive Electrode (TCE) is an essential part of the optoelectronic and display devices such as Liquid Crystal Displays (LCDs), Solar Cells, Light Emitting Diodes (LEDs), Organic Light Emitting Diodes (OLEDs) and touch screens. Indium Tin Oxide (ITO) is a commonly used TCE in these devices because of its high transparency and low sheet resistance. However, scarcity of indium and brittle nature of ITO limit its use in future flexible electronics. In order to develop flexible optoelectronic devices with improved performance, there is a requirement of replacing the ITO with a better alternate TCE. In this work, several alternative TCEs including transparent conductive oxides, carbon nanotubes, conducting polymers, metal nanowires, graphene and composites of these materials are studied with their properties such as sheet resistance, transparency and flexibility. The advantage and current challenges of these materials are also presented in this work.
This paper presents some construction analysis and test results of a Free Space Optics system operating at the wavelength of 9.35 μm. In the system, a quantum cascade laser and a photoreceiver with mercury cadmium telluride photodetectors were used. The main parameters of these elements were discussed taking into account a data link operation. It also provides to determine a data range for various weather conditions related to scattering and scintillation. The results of numerical analyses defined the properties of currently available FSO technologies working in the near infrared or in the short infrared range of spectrum versus the performances of the developed system. The operation of this system was verified in three different test environments. The obtained results may also contain important issues related to the practical application of any FSO system.
49th Winter School on Wave and Quantum Acoustics constituted platforms for sharing the results and achievements obtained in different branches of physical acoustics, as molecular acoustics, quantum acoustics, acousto-optics, magnetoacoustics, photoacoustics, acoustics of solid state, acoustic emission, and others. Moreover, researches in some selected topics related to those mentioned above (e.g. optoelectronics, relaxation processes) were presented during the school.
The conference consisted of the 16th Workshop on Acoustoelectronics and the 16th Workshop on Molecular Acoustics, Relaxation and Calorimetric Methods. However, the organizers are opened to organizing workshops on other subjects in future. We would like to invite scientific centers and other professional groups to cooperate in organizing workshops on the subjects of their interests.
XLVIIIth Winter School on Environmental Acoustics and Vibroacoustics was a forum for all environmental and vibroacoustics fields. Particularly it was concerned with traffic noise, vibroacoustics of machines, room acoustics, building acoustics, noise protection and similar problems. During the Conference, seminars on “Measurement of noise and vibration at the workplace” and Environmental noise monitoring”, combined with measurement workshops, were organised in association with SVANTEK.
The Conferences began with the special, joined session dedicated to celebration of the 15th Jubilee Conference Integrated Optics – Sensors, Sensing Structures and Methods. In summary, 48 people participated in Conferences and seminars, presenting 37 lectures, reports and posters. In this issue one can find abstracts of some lectures and posters, which were presented during the Conferences.