The paper presents the experimental results obtained using a laboratory setup installation for fluorescence excitation of CdTe QDs used as biomarkers for clinical diagnostics. Quantum Dots (QDs) made of Cadmium Telluride (CdTe), are highly fluorescent and they are used as robust biomarkers. Generally, QDs are referred to as the zero-dimensional colloidal crystals that possess strong size dependence and multi-colored luminescence properties. Along with its intrinsic features, such as sharp and symmetric emission, photo-stability and high quantum yields, QDs play a vital role in various applications, namely the identification of the chemical moieties, clinical diagnostics, optoelectronics, bio-imaging and bio-sensing1.
Minuscule devices, called RFID tags are attached to objects and persons and emit information which positioned readers may capture wirelessly. Many methods of identification have been used, but that of most common is to use a unique serial number for identification of person or object. RFID tags can be characterized as either active or passive [1,2]. Traditional passive tags are typically in “sleep” state until awakened by the reader’s emitted field. In passive tags, the reader’s field acts to charge the capacitor that powers the badge and this can be a combination of antenna and barcodes obtained with SAW( Surface Acoustic Wave) devices [1,2,3] . The antenna in an RFID tag is a conductive element that permits the tag to exchange data with the reader. The paper contribution are targeted to antenna for passive RFID tags. The electromagnetic field generated by the reader is somehow oriented by the reader antenna and power is induced in the tag only if the orientation of the tag antenna is appropriate. A tag placed orthogonal to the reader yield field will not be read. This is the reason that guided manufacturers to build circular polarized antenna capable of propagating a field that is alternatively polarized on all planes passing on the diffusion axis. Passive RFID tags are operated at the UHF frequencies of 868MHz (Europe) and 915MHz (USA) and at the microwave frequencies of 2,45 GHz and 5,8 GHz . Because the tags are small dimensions, in paper, we present the possibility to use circular polarization microstrip antenna with fractal edge .
At long ranges and under low visibility conditions, Advanced Optoelectronic Device provides the signal-to-noise ratio and image quality in the Short-wave Infra-red – SWIR (wavelengths between 1,1 ÷2,5 μm), significantly better than in the near wave infrared – NWIR and visible spectral bands [1,2]. The quality of image is nearly independent of the polarization in the incoming light, but it is influenced by the relative movement between the optical system and the observer (the operators' handshake), and the movement towards the support system (land and air vehicles). All these make it difficult to detect objectives observation in real time.
This paper presents some systems enhance which the ability of observation and sighting through the optical systems without the use of the stands, tripods or other means. We have to eliminate the effect of "tremors of the hands" and the vibration in order to allow the use of optical devices by operators on the moving vehicles on land, on aircraft, or on boats, and to provide additional comfort for the user to track the moving object through the optical system, without losing the control in the process of detection and tracking. The practical applications of stabilization image process, in SWIR, are the most advanced part of the optical observation systems available worldwide [3,4,5]. This application has a didactic nature, because it ensures understanding by the students about image stabilization and their participation in research.
The results of research into Surface Acoustic Wave – SAW – filters have been recognized for their efficiency and
versatility in the electrical signals processing 1,3. Gallium Orthophosphate (GaPO4) is a relative new material, which has a long term high stability and, moreover, has an excellent behavior with temperature variation 2,3. The characterization of SAW filters based on GaPO4 is uses the comparative analysis of simulated results of parameters, with different software programs, which were developed for designing of these filters. Simulation covers the determination and analysis of the characteristics of this filter, namely, mechanical parameters (constructive) and operational parameters in comparison with the design data. In order to obtain the parameters of SAW filters we have used the algorithms and software for modelling, simulation. The paper presents several versions of software programs, in Matlab and Microsoft Visual C#, for the design of GaPO4 SAW filters and their interpretation. These modeling, simulations were performed successively by each program, until we set the parameters of SAW filter. By the comparison of the data obtained with each program, we have improved the constructive dimensions of fingers, we obtained the desired parameters. With this data, we realised SAW filters based on GaPO4, and with the help of the Network Analyzer we measured parameters of the filter, which are presented in the paper2,10.
Optoelectronics is facing with an ever dynamic increasing in our lives. We feel a growing demand for specialists in design and operation of optoelectronic systems. In accord with this demand Politehnica University of Bucharest (PUB) has introduced optoelectronics curricula since 1992 year. The theoretical courses are covered by laboratory activities, to provide the students with actual experience of optoelectronic systems. Some experiments are presented in this paper. To get a good efficiency of experiments, the student should study Laboratory guide manual, before entering the laboratory. PUB in collaboration with SPIE organization is intending to develop an integrated optoelectronics laboratory for education ofoptoelectronics specialization students with the following principles: define the educational goals and experimental laboratory courses to fulfill the objectives, design the instrumentation and systems to enable practical, experimental investigation and measurements; elaboration of experimental algorithms and laboratory guide for students, which include exercises and problems with responses connected with real world of optoelectronics specialists demand. This paper focuses on the presentation of laboratory courses that would be developed a meaningful understanding of optoelectronic devices, and systems.
The number of radio frequency surface acoustic wave (SAW) filters produced presently exceeds 3 billion per year. The
demand for high-frequency SAW filters for telecommunications and remote sensing, has led to extensive research,
focusing on new SAW microdevices. SAW devices have shown compact structures, small size, low cost, high sensitivity
and fast response. The need of miniaturized systems, with high sensitivity and low energy has motivated the need to
integrate on the same substrate all the structure of SAW device and connecting electronic circuits. As a consequence,
many types of methods of both constructive and operating characterization of SAW devices have been developed. This
paper provides a short introduction regarding the developed level of SAW microdevices and describes the results of
literature investigation research of optoelectronic techniques for constructive characterization of SAW microdevices.
Further research will be done into the determination of SAW parameters such as the amplitude of surface wave, the
velocity of wave propagation on the surface of the piezoelectric substrate. Substrates of quartz, lithium tantalite (LiTaO3)
and lithium niobate (LiNbO3), are piezoelectric materials commonly used in manufacturing of SAW devices, but these
materials are not compatible with the integrated circuit (IC) technology. Three optoelectronic measurement techniques
are known for detection of surface acoustic waves: diffraction grating technique, the knife-edge technique, and the
detection of ultrasonic vibrations using optical interferometry. The research work given in this paper concentrates on
describing of optoelectronic techniques used for constructive characterization of SAW microdevices. Finally, we try to
draw some conclusion where: optoelectronic techniques are predicted to be one of the fundamental measurement
methods for measurement of future SAW microdevices.
Over the years extensive studies have been carried out to apply coherent optics methods in real-time processing,
communications and transmission image. This is especially true when a large amount of information needs to be
processed, e.g., in high-resolution imaging. The recent progress in data-processing networks and communication
systems has considerably increased the capacity of information exchange. We describe the results of literature
investigation research of processing methods for the signals of the three-dimensional images. All commercially available
3D technologies today are based on stereoscopic viewing. 3D technology was once the exclusive domain of skilled
computer-graphics developers with high-end machines and software. The images capture from the advanced 3D digital
camera can be displayed onto screen of the 3D digital viewer with/ without special glasses. For this is needed
considerable processing power and memory to create and render the complex mix of colors, textures, and virtual
lighting and perspective necessary to make figures appear three-dimensional. Also, using a standard digital camera and
a technique called phase-shift interferometry we can capture "digital holograms." These are holograms that can be
stored on computer and transmitted over conventional networks. We present some research methods to process "digital
holograms" for the Internet transmission and results.
In this paper we are going to present some results regarding the optical trapping and manipulation of dielectric
microparticles immersed in fluids. The experiments will be done in Mie regime, i.e diameter of the particles is larger
than the laser wavelength. We will report optical trapping of multiple particles and their manipulation by means of
optical tweezers setup. To catch microobjects we will use a Gaussian laser beam and to manipulate them we are going to
calculate diffractive optical elements (DOEs) by iterative algorithm and spherical wave method.
In so rapidly growing sensing technology, Autonomous Surface Acoustic Waves (SAW) based sensors, offer high
flexibility for modern identification/sensing systems, and represent a new perspective for remote monitoring and
control. This paper gives a presentation of operating principles of wireless SAW sensors with separation in
frequency (frequency domain division-FDD) and separation in time (time domain division-TDD). The design of
interdigitated transducers (IDT), and reflectors on the different types of substrate materials as piezo crystals LiNbO3,
LiTaO3 or quartz in connection with application domains is presented. A comparison between Time Domain
Sampling-TDS and Frequency Domain Sampling-FDS principles of transmitter and receiver, gives evidence of their
advantages and disadvantages. A part of the paper dealt with the measurement results.
In this paper, the performance of PSK (phase shift keying) homodyne system in the present of laser phase noise is
calculated. It is shown that the phase noise leads to a significant performance degradation for coherent systems. The
obtained results are shown graphcally.
One of the most critical components of a PSK receiver is the PLL. A technique that makes possible to avoid a PLL device is based on the transmission of a reference carrier together with the modulated signal. The carrier can be extracted at the receiver end for demodulation. In this paper is made an analysis from the point of view of the performances of this kind of system and the main purpose is to minimize the error probability searching a suitable power splitting ratio at the transmitter.
The taper (i.e. thin fiber with transitions from large to small diameter) is created during pulling of the molten fiber. Its shape depends on many parameters of the pulling process, such as pulling speed, pulling temperature, pulling stages step, etc. This paper attempts to describe the taper shape as a function of pulling parameters and provide comparison for different heating methods.
In this paper we analyze the electromagnetic modes in photonic crystals. This is important because of the wide range of potential applications of structures which allow a complete control over light propagating in them. We focus to study the fundamental behavior of one- and two-dimensional photonic crystals, which are easier to investigate than three-dimensional structures. We will study the photonic band structure in the TM modes (E-polarization) and in the TE modes (H-polarization).