Abstract: Films of transparent semiconductors are widely studied and developed because of high potential applications in electronics in last decade. Our work concerns the properties of NiO films fabricated by RF magnetron sputtering. Electrical and optical parameters of the films were characterized using Hall and transmittance measurements, respectively. P-type conductivity of as-deposited films and after annealing in oxygen or argon at the temperature range from 300 °C to 900 °C was verified. Transmittance of NiO films strongly depends on deposition temperature and oxygen amount during sputtering. Films deposited at room temperature without oxygen have transmittance near 50% in the visible range and resistivity about 65 Ωcm. An increase in oxygen amount in deposition gas mixture results in higher conductivity, but transmittance decreases below 6%. Resistivity of 0.125 Ωcm was attained at sputtering in oxygen. Films deposited at temperature elevated up to 500 °C are characterized by transmittance above 60% and lower conductivity. Annealing of NiO films in Ar causes resistivity to rise dramatically.

Abstract: There has been much research about using Gabor wavelet for face recognition. Other multiscale geometrical tools, such as curvelet and contourlet, have also been used for face recognition, thus it is interesting to know which method performs best, especially under illumination and expression changes. In this paper, we make a systematic comparison of wavelet, Gabor and curvelet for recognition, and find the best subband irrelevant to expression and illumination changes. We combine the multiscale analysis with subspace decomposition as our algorithm. Experiments show that for expression changes, the properties of the coarse layer of curvelet and wavelet are very good. Whilst for illumination changes, the low frequency parts of the two methods are similarly influenced, but the detail coefficients of curvelet and the high frequency of wavelet work fine with PCA, with the former outperforming the latter. When these two factors change simultaneously, the detail layer of curvelet is better relative to the others.

Abstract: The paper presents the investigation into a possible new photovoltaic (PV) application of carbon nanotube-based elastic layers, manufactured by a screen-printing technique. The optical and mechanical properties of these layers are investigated and compared with ITO, standard transparent conductive oxide utilized in photovoltaic devices. Simulations of new TCO layer functioning in various solar constructions are performed. Finally, first results of a test silicon cell, contacted by proposed material, are reported.

Abstract: The cross-linked chitosan is synthesized by homogeneous reaction of medium molecular weight chitosan in aqueous acetic acid solution with glutaraldehyde as cross-linking agent. Using surface plasmon resonance technique, the optical properties of cross-linked chitosan thin film before and after contacting with different concentrations of copper ion in a range of 0 to 100 ppm had been obtained by fitting. The imaginary part of refractive index increased while the thickness of the film decreased as copper ion concentration increased from 0 (deionised water) to 100 ppm. The resonance angle shifted to lower value as the copper ion concentration increased. By introducing the cross-linked chitosan film, copper ion detection can be obtained for concentration as low as 0.5 ppm using surface plasmon resonance technique.

Abstract: Silver nanowire filled photonic crystal fibers are proposed in this paper to achieve surface plasmon resonance sensors and overcome the complicacy and difficulty of coating the holes in the photonic crystal fiber. Optical field distributions of these fibers at different wavelengths are calculated and simulated using the finite element method (FEM), and the sensing properties are discussed in both areas of resonant wavelength and intensity detection. Numerical simulation results show that carefully designed structure of the sensor brings about an excellent effect, with both spectral and intensity sensitivity in the range of 4×10 –5 –5×10 –5 RIU, better than in the case of similar structures coated with metal film, and the fabrication is expected to be simplified.

Abstract: Corresponding author: [email protected] paper presents general information on ceramic microsystems. Low temperature co-firedceramics (LTCC) technology is described in detail. Research and development on the LTCCsensors and microsystems carried out at Wroclaw University of Technology (Poland) arepresented. Microfluidic system, polymerase chain reaction (PCR) microreactor, accelerationsensor and sol–gel fiber optics for ceramic microsystems are described. Keywords: low temperatur e co-fired ceramics (LTCC), microsyst em, polymerase chain reaction (PCR),microreactor.

Abstract: In this work, structural and optical properties of vanadium oxides have been presented. Thin films were manufactured by microwave-assisted magnetron sputtering process. Particles were sputtered from a vanadium target in Ar/O 2 atmosphere. Oxygen partial pressure was changing from 3×10 –4 to 7×10 –4 Torr. After the deposition, the thin films were additionally annealed at 400 °C in ambient air in order to oxidize the films. Structural investigation was performed with the aid of X-ray diffraction measurements and Raman spectroscopy. The results obtained from both methods have revealed that as-deposited films were amorphous, while annealed films had V 2 O 5 crystal form. Optical properties were determined by transmission measurements in the spectral range from 250 to 2500 nm. As-deposited films had low transmission (below 10%), but oxidization by additional annealing of the structure resulted in the increase of the transmission level up to about 20 and 43% at 650 nm wavelength for samples prepared under 3×10 –4 and 7×10 –4 Torr oxygen partial pressure, respectively. The analysis of the structure and optical properties of the thin films has revealed the influence of deposition parameters on the properties of vanadium oxides.

Abstract: An extensive theoretical analysis is carried out to investigate the variation of the sensitivity of optical slab waveguide sensors with the wavelength of the guided wave. We consider a three-layer waveguide as an optical sensor. The sensitivity for both polarizations of light: s-polarized light (TE) and p-polarized light (TM), is derived using the characteristic equation of the structure. The dispersion of the materials is taken into account to study the sensitivity spectroscopic scan over the near IR-range from 1.2 –2 μm. It is found that an optimum wavelength exists for each guiding layer thickness and this optimum value increases linearly with the thickness of the guiding layer.

Abstract: In this paper, the Monte Carlo technique is used to determine the optical detection strategies in three-layered (maternal, amniotic fluid and fetal) tissue model. This model is utilized to estimate the transabdominal optical power and optimum source–detector (S–D) separation. Results based on the launching of 2 million photons with 1 mW optical power showed that the expected optical power output is in the range of 10 –6 –10 –10 W/cm 2 depending on S–D separation. Considering the limit of the signal processing methods (such as adaptive noise cancelling) and the use of silicon photodetector, an S–D separation of 4 cm has been selected as a practical compromise between signal level and percentage of optical power (70%) coming from the fetal layer. Based on these findings, transabdominal fetal heart rate detection system using NIR and adaptive filtering can be designed and developed.

Abstract: The prismatic structures for excitation surface plasmon polariton and waveguide modes resonances were investigated. The first structure consists of a glass prism and thin metallic layer deposited on the prism. The second one includes an additional dielectric layer. Plasmon polariton resonance can be observed only for TM polarization at finely tuned structure parameters. Waveguide modes resonance is possible for both polarizations in the presence of the dielectric layer. We show that the first structure has the highest sensitivity of angle minimum reflectivity, whereas the second one has the highest reflectivity sensitivity to the probed liquid refractive index changes.

Abstract: SnS thin films were electrodeposited on ITO (indium tin oxide) glass substrates maintained at different temperatures using aqueous solutions containing 33 mM of SnCl2 and 91 mM of Na2S2O3·5H2O The films were characterized to study the structural, morphological and optical properties The X-ray diffraction studies of the films show the polycrystalline nature with orthorhombic crystal structure Microstructural parameters such as crystallite size, microstrain, and dislocation density were calculated with respect to various temperatures The scanning electron microscope (SEM) studies reveal good surface morphology with a large number of grains at the optimized temperature The optical band gap of the SnS film was determined from optical transmittance data, in the spectral range 400–1100 nm and the direct band gap energy (Eg ) was found to be 12 eV, which does agree well with earlier reported values Fourier transform infrared spectroscopy (FTIR) studies confirm the presence of SnS films in the molecular structure

Abstract: Gallium phosphide (GaP) thin film was prepared by an asymmetric bipolar pulsed-dc magnetron sputtering technique onto glass substrate at room temperature in an Ar atmosphere. A compacted GaP powder was used as a target. The X-ray diffraction patterns show that the film is amorphous. The transmittance of the film was measured in the incident photon wavelength range of 300 –2 000 nm. The film’s refractive index, thickness and absorption coefficient as a function of wavelength were determined by using Swanepoel’s method. The deduced absorption data indicate that the optical transition in the film is dominated by the indirect type. The corresponding energy of 1.51 eV was obtained for the 563 ±16 nm thin film.

Abstract: Cu and Fe doped cadmium sulfide nanoparticles were prepared with a wet chemical synthesis by mixing the reactants in double distilled water solvent. Thioglycerol (TG) was employed as the capping agent and also the reaction catalyst. The estimated particle size of prepared samples was found in the range 3–4 nm. Properties of particles were investigated using photoluminescence spectroscopy (PL) and X-ray diffraction analysis (XRD). XRD pattern of samples reveals a hexagonal crystal structure at room temperature. We have studied effect of doping and TG concentration on the luminescence of doped CdS nanocrystals. There is a noticeable increase of the PL intensity when TG concentration increased. The PL spectra include two bands, due to emission of traps and surface state.

Abstract: In this paper, we will focus on the modulation format used to create the optical pulses, which are return-to-zero (RZ), and non-return-to-zero (NRZ). Bit error rate (BER) performance is evaluated based on double weight (DW) code. Optical code division multiple access (OCDMA) system is considered a promising technique for fiber-to-the-home (FTTH) access networks. The performance of RZ against NRZ is compared through simulation by using the Optisystem software version 7. We used two networks designed as follows: one used a RZ pulse generator and the second used a NRZ pulse generator, and both systems were tested with and without erbium doped fiber amplifier (EDFA). It has been found that the NRZ pulse generator in this system is better than the RZ pulse generator for all simulation results. The conversion used a Mach –Zehnder interferometer (MZI) wavelength converter. Also, we are proposing a detection scheme known as the AND subtraction detection technique implemented with fiber Bragg grating (FBG) which acts as an encoder and decoder. This FBG is used to encode and decode the spectral amplitude coding DW code in the OCDMA system. The performances are characterized through BER and bit rate (BR), and also the received power at various bit rates.

Abstract: We have investigated the light intensity distributions of a 7-inch LGP to increase output illuminance uniformity by reducing the bright and dark areas caused by a plurality of LED. We analyzed the effects of the LED–LED gap and LED–LGP space to the light intensity distribution in the LGP inside. We have found that the density function of LGP pattern has a simple exponential terms. We analyzed the output light intensity of the LGP through the comparison of the simulation results between adopting the hemisphere pattern density function and adopting the equidistance pattern density function. And also, to reduce the bright spot and dark areas, we have introduced a convex elliptical LED reflector. As a result, the output illuminance uniformity was improved effectively by the adoption of the pattern density function and the new LED reflector.

Abstract: X-ray reflectivity (XRR) is one of the primary measurement techniques for thickness calculation of thin films and multilayer period determination. This technique can also be used for the analysis of organic thin film multilayer structures. In this method, the accuracy of thickness calculation depends on precision of the determination of the local maxima of XRR curve. The analysis of the XRR curves is cumbersome because of the noise which is recorded while measurement. It can be improved using computer data analysis algorithms for noise reduction and determination of the local maxima on the XRR curve. One of such algorithms, widely used in the data spectroscopy analysis, is Savitzky–Golay (S–G) algorithm. In this paper, the application of S–G algorithm for thickness determination of self-assembled ion liquid nanolayer of dimethyldiallylammonium chloride (PDDA) is shown.

Abstract: A new configuration of all-optical 4-bit parity checker is proposed that incorporates six semiconductor optical amplifiers (SOAs). The proposed 4-bit parity generator is numerically simulated by solving nonlinear coupled equations that explain the cross gain modulation (XGM) effect in individual SOAs. The full design is easy to understand. The outputs can be tested at every step with the help of waveforms. This makes easy error analysis of the circuit. The fault detection and correction can be made comfortably. This design proves that when we reach up to chip level design, the economical circuit is integration capable.

Abstract: The DNA (deoxyribonucleic acid) amplification chip made of DP951 (from DuPont) ceramics consists of a microchamber, internal and external metallization. The external metallization is used for attachment of SMD (surface mount device) electronics elements. The internal metal layer improves thermal conditions inside the chamber. The temperature distribution in the chamber is verified by numerical simulation. Heating is realized by an external SMD resistor. The temperature measurements are made by attached Pt100 component. The temperature control is realized by a microcontroller based electronic system. Settings and visualization of the polymerase chain reaction (PCR) process parameters are actualized by dedicated PC (personal computer) software. The system is successfully tested. The DNA amplification inside the low temperature co-fired ceramics (LTCC) chip is achieved.

Abstract: Rapid development of analytical microsystems, also often called as labs-on-a-chip and used to perform various chemical and biochemical analysis with nano- and pico-volumes of the sample, has been observed for almost two decades Successful application of analytical microsystems in medical and veterinary practices is relevant to many factors but one of them is low price of the disposable microsystem – often in the form of a chip The chips are made of cheap materials, for example, polymers One of such material is a negative photoresist SU-8 It is characterized by biocompatibility and possibility of easy fabrication of various three-dimensional fluidic microstructures Moreover, SU-8 is transparent for visible light It makes SU-8 attractive material for labs-on-a-chip dedicated for genetic material analysis by real-time polymerase chain reaction (PCR) In this paper, we present the results of investigations of the influence of PCR-like temperature profiling on the transmittance spectra The autofluorescence effect of SU-8 illuminated with various lasers has also been investigated as one of the factors limiting sensitive fluorescence readout The results obtained showed that SU-8 can be successfully applied as labs-on-a-chip material but, due to high SU-8 autofluorescence, red-line fluorochromes are preferred when high-sensitivity fluorescence detection is required

Abstract: This paper offers a novel algorithm to better design LEDs arrays for illumination systems. First, the illuminance distribution of LED arrays is studied through theoretical analysis. Second, we present the algorithm criterion and steps. And finally, we use computer to simulate and verify this method. The results show that the illumination uniformity is significantly affected by the spacing of each light in the LED array. The analysis method presented here in this thesis can be usefully applied in LED in the illumination engineering.

Abstract: In this paper, we present a theory concerning low-frequency modal noise in the cascade of couplers. This theory enables calculation of signal-to-noise ratio in cascade connection of multimode couplers. We provide a series of numerical calculations based on the model for different realizations of the couplers.

Abstract: We propose an eight-channel all-optical switch using a multimode interference phenomenon. This structure is based on the cooperation of self imaging and self guiding in nonlinear multimode interference. The switching operation is done with changing the intensity of the input signal. To the best of our knowledge, this is for the first time that a 1×8 all-optical switch is presented based on a continuous multimode interference region. Simulation results show low crosstalk and high efficiency in the output profiles. The mean values of the crosstalk and the insertion losses in eight states of the switching operation are – 33.8 dB and –0.16 dB, respectively. Full-vectorial beam propagation method is used for the simulation of the device.

Abstract: To deal with illumination variations in face recognition, a novel two-stage illumination normalization method is proposed in this paper. Firstly, a discrete cosine transform (DCT) is used on the original images in logarithm domain. DC coefficient is set based on the average pixel value of all the within-class training samples and some low frequency AC coefficients are set to zero to eliminate illumination variations in large areas. Secondly, local normalization method, which can minimize illumination variations in small areas, is used on the inverse DCT images. This makes the pixel values on the processed images be close to or equal to that of the normal illumination condition. Experimental results, both on Yale B database and Extended Yale B database, show that the proposed method can eliminate effect of illumination variations effectively and improve performance of face recognition methods significantly. The present method does not demand modeling step and can eliminate the effect of illumination variations before face recognition. In this way, it can be used as a preprocessing step for any existing face recognition method.

Abstract: Significant amount of emitted light from an organic light emitting diode (OLED) is trapped as a result of total internal reflection (TIR) on a glass–a ir interface. One of the strategies to increase the light extraction efficiency is using a scattering thin film. A model is built using the Monte Carlo ray tracing method to simulate Mie scattering. Almost 100% of light trapped by the TIR can be extracted if the radius of the spherical scatters, the refractive index ratio between the matrix and the scatter and the concentration of the scatter are optimized. The implication is important for a high efficiency OLED used in the next generation lighting source.

Abstract: A study of manufacturing micromirrors inclined at 45° towards silicon substrate has been presented in this paper. The micromirrors can be formed by {100} or {110} sidewall planes etched in (110) or (100) Si substrates in alkaline solutions. The smoothness of the surface and etch rate anisotropy are crucial parameters of fabricated structures. The research focused on Si(100) wafers etched either in KOH solutions with alcohol additives or in low concentrated TMAH solutions with surfactant addition and on Si(110) wafers etched in pure highly concentrated KOH or TMAH solutions. The examination showed difficulty of fabrication of the structures with smooth sidewalls and with appropriate shape simultaneously. At the end of the paper, the structure for bringing close and parallel of two optical beams has been proposed.

Abstract: In order to enhance the visual quality of images obtained by underwater imaging systems, super resolution (SR) reconstruction is introduced, including single-frame and multi-frame SR algorithms. Experimental images from a range-gated pulsed laser imaging system are processed by SR algorithms, results are evaluated and compared by blind, objective quality metrics. Results show that the image quality of underwater imaging can be effectively enhanced if the appropriate SR reconstruction algorithm is chosen.

Abstract: Rib waveguides were fabricated with the use of selective, wet chemical etching of two-component waveguide films SiO2:TiO2 which were obtained using the sol–gel method. Photoresist was applied as a mask in the process. The etching of the layers SiO2:TiO2 was carried out in water solutions of ammonia fluoride. The paper presents the results of theoretical analysis as well as the power distributions in the obtained strip waveguides and directional couplers.

Abstract: This paper reviews the current state of art of vacuum encapsulation of microsystems. Different types of bonding techniques and “integrated sealing process” are described. It is concluded that the step forward in vacuum sealing of MEMS structures should be elaboration of MEMS-type micropump, which would be integrated with microsystem structure. A novel concept of a miniature orbitron pump is presented. It is also reported how vacuum inside the micropump can be measured. It is proposed that for measurement of a low vacuum level, a membrane sensor can be used, and for a high or ultra-high vacuum level an ionization sensor. Both sensors should be integrated with a micropump structure. The results of membrane sensor study are presented.