Series of hydroxyapatite (HA) coatings deposited on titanium substrate at different spray (plasma gun to workpiece) distance were investigated. The optical methods as dark field confocal microscopy, Raman/PL and UV-VIS spectroscopy were used for study the influence of deposition process on structural degradation of HA precursor. The hydroxyl group concentration was investigated by study the OH mode intensity in the Raman spectra. Optical absorption coefficients at near UV region were analyzed by Diffuse Reflectance Spectroscopy. PL intensity observed during Raman measurement was also considered as relation to defects concentration and degradation level. It was confirmed the different gunsubstrate distance has a great impact on structure of deposited HA ceramics.
Carbon nanotube (CNT) films deposited on different porous silica substrates were studied by Scanning Electron Microscopy (SEM) and Raman Spectroscopy (RS). The films samples were prepared by a two-step method consisting of PVD and CVD processes. In the first step the nanocomposite Ni-C film was obtained by evaporation in dynamic vacuum from two separated sources of fullerenes and nickel acetate. Those films were deposited on porous silica and DLC/porous silica substrates. Analysis of SEM imaging showed that the obtained film are composed of carbon nanotubes, the distribution, size and quality of which depend on the type of substrate. The CNT films were studied by RS method to determine the influence of the substrate type on disordering of carbonaceous structure and quality of CNT in deposited films.
Raman spectra of TiO2 anatase prepared by sol-gel method were measured and analyzed by Principal Component Analysis (PCA) method. The pure and Ag-doped powder samples of TiO2 were prepared in different routes and calcined in air at the same temperature of 550°C. For every sample, nine spectra were measured using microRaman Nicolet Almega XR spectrometer at 532nm excitation and 6mW input beam power. The spectra were processed by PCA algorithm by means of PCA Model Editor and Analysis software (Jasco). Analysis shows the difference between commercially available anatase (Sigma Aldrich) and samples prepared in sol-gel method. The PCA coefficients can be easily separated in PCs space. The components related to the anatase and rutile phases were also extracted. Moreover, spectra of Ag-doped anatase can be clearly distinguished. It was shown the PCA method is useful for classification of anatase samples prepared in different technology conditions.
The TiO2 coatings were prepared by simple sol-gel method and modified by UV pulsed laser. TiO2, also know as titania, is a ceramic compound, existing in numerous polymorphic forms, mainly as tetragonal rutile and anatase, and rhomboidal brookite. Rutile is the most stable form of titanium dioxide, whereas anatase is a metastable form, created in lower temperatures than rutile. Anatase is marked with higher specific surface area, porosity and a higher number of surface hydroxyl groups as compared to rutile. The unique optical and electronic properties of TiO2 results in its use as semiconductors dielectric mirrors, sunscreen and UV-blocking pigments and especially as photocatalyst.
In this paper, the tetraisopropoxide was used as Ti precursor according to sol-gel method. An organic base was applied during sol preparation. Prepared gel was coated on glass substrates and calcined in low temperature to obtain amorphous phase of titania. Prepared coatings were modified by UV picosecond pulse laser with different pulse repetition rate and pulse power. Physical modification of the coatings using laser pulses was intended in order change the phase content of the produced material. Raman spectroscopy (RS) method was applied to studies of modified coatings as it is one of the basic analytical techniques, supporting the identification of compounds and obtaining information about the structure. Especially, RS is a useful method for distinguishing the anatase and rutile phases. In these studies, anatase to rutile transformation was observed, depending on laser parameters.
Titanium oxide displays, among others, catalytic and bactericidal properties, as well as the capacity to absorb UV radiation. The properties may differ significantly depending on the phase composition. This is why for the prospective applications it is necessary to determine the effect of the obtaining process parameters on the phase composition and, consequently, on the properties of the obtained samples. In our work we present results of Raman spectroscopy and X-ray diffraction studies of TiO2 layers obtained in sol-gel method. The work will present effects of calcination temperature on the structure of the obtained layers. Raman Spectroscopy is a useful method of identification, allowing to distinguish the anatase phase from the rutile phase.
In this paper the preparation process and optical characterization of pure and Al3+ doped zinc oxide (Al:ZnO) coatings will be presented. ZnO based materials have been studied extensively due to their potential applications in optoelectronic devices as conductive gas sensors, transparent conductive, electrodes, solar cell windows, varistors, UVfilters or photovoltaic cells. It is II–VI semiconductor with wide-band gap of 3.37 eV and large exciton binding energy of 60meV. It is possible to improve the conductivity of ZnO coating by intentionally doping ZnO with aluminium ions during preparation process. Such transparent and conducting thin films, known as AZO (Aluminium Zinc Oxide) films, are very good candidate for application as transparent conducting materials in many optoelectronic devices. The well-known sol-gel method is used for preparation of solution, coated on glass substrates by dip coating process. Prepared samples were investigated by Raman and UV-VIS spectroscopy. Transmittance as well as specular and diffuse reflectance spectroscopy methods were used for studies of optical parameters. We found that Al admixture influences on optical bandgap of ZnO.
In this paper we show how PCA (Principal Component Analysis) method can be implemented using Java programming language. We consider using PCA algorithm especially in analysed data obtained from Raman spectroscopy measurements, but other applications of developed software should also be possible. Our goal is to create a general purpose PCA application, ready to run on every platform which is supported by Java.
The thin films of carbon-nickel (C-Ni) nanocoposites were deposited on Ti-evaporated Si (100) substrate using Physical Vapour Deposition (PVD) method. Influence of evaporated titanium on carbonaceous structure of C-Ni films were investigated by Raman spectroscopy method. The fullerite-graphite structure was recognize using principal component analysis (PCA) of obtained Raman spectra.
Hydroxyapatite (HAp) is a well-known bioceramic, nonorganic material of the bones of the vertebrate responsible for their mechanical durability. In human bones it occupies 60-80 % of the volume depending on a number of factors. Synthetic HAp is valued in bone endoprosthetic to its high biocompatibility. It is widely used to fill cavities of bone and as the coating of bone implants to increase their biocompatibility and adhesion to bone surface. In this paper a diffuse reflectance spectra of plasma-spraying deposited hydroxyapatite were presented and compared with pure powder samples. Optical band gap were estimated basing on Kubelka-Munk functions and Tauc plot extrapolation. We found that deposition process affects the value of band gap.
This paper deals with some of the WEP (Wired Equivalent Privacy) key decryption methods based on aircrack-ng
software, which was embedded in Backtrack operating system (Linux distribution). The 64-bit (40-bit) and 128-bit (104-
bit) key encrypted with RC4 cipher weakness was shown. Research methods were made in different network
environments. In this work we compared different types of keys to check how strong the RC4 stream cipher can be. The
40-bit and 104-bit WEP key has been tested on IEEE 802.11 based wireless LAN using laptop with live-CD Linux
operating system. A short analysis of key creation methods was performed to compare the amount of time necessary to
decrypt random and nonrandom WEP keys.
In this paper some optical properties of carbonaceous-palladium (C-Pd) thin films investigated using UV-VIS-NIR
spectroscopy method are presented. Transmittance and reflectance spectra were measured in 200-3200 nm region. The
shape of the spectra were depended on allotropic form of carbon (fullerene) matrix. The refractive coefficients and film
thickness of studied materials has been determined based on Thin Film Interference and “envelope” methods. The
optical band gap values were also estimated from absorption spectra using Tauc plot extrapolation. The results are in
good agreement with experimental data obtained by spectroscopic ellipsometry.
In this paper influence of hydrogen on molecular structure of carbonaceous-palladium (C-Pd) films using Raman and
FTIR spectroscopy methods has been studied. The special experimental setup (gas cell) was design and realized. The
spectra were measured in H2/N2 atmosphere under different gas pressure and flow rate and compared with base spectra
measured in air. The noticeable influence of gas flow on intensity of some bands in FTIR spectra were observed.
Understanding of role of H2 in interaction with C-Pd film needs other experimental works. Observed phenomenon can
be used in construction of optical hydrogen sensor.
In this paper an influence of the content of palladium on optical properties of fullerene-palladium nanocomposite was discussed, based on Effective Medium Theory (EMT). Since the complex refractive index of Pd is clearly different from the refractive index of fullerene, even a small admixture of metal leads to significant changes in value of effective index and consequently to change the reflection coefficient of the layer.
In this paper, the results for thin carbon-palladium (C-Pd) nanocomposites obtained by PVD (Physical Vapour Deposition) and PVD/CVD (Chemical Vapour Deposition) method, carried out using Raman spectroscopy method are presented. Studies reveal the dominance of fullerene-like structure for PVD samples and graphite-like structures for CVD samples. The type of substrate and metal content have great impact on spectra shapes.
In this paper, the preliminary results for thin carbon-palladium (C-Pd) nanocomposites obtained by PVD/CVD method,
carried out using optical methods are presented. Raman studies reveal the dominance of graphite-like structures. The
optical transmittance measurement shows an exceptionally low value of the effective extinction coefficient when
compared to amorphous graphite. The carbon structure porosity impact on the transmission properties of the studied
layers is discussed.
Ni-C nanostructures are the interesting object of study due to their potential use in field-effect electron emitters.
Investigations of the structures are typically carried out using experimental methods as molecular spectroscopy (FTIR
and Raman). The aim of these investigations is study the influence of metal atoms on formation of carbon structure.
These studies may be expanded through the using of quantum mechanics calculation software.
Some aspects of using a Hyperchem software in study of Ni-C structures will be presented. The simulations were
made for typical structures of carbon (C60 fulleren and graphene) surrounded by metal atoms. The usefulness of the
software in the quantum-mechanics calculations is analysed.
The results of Raman and SEM studies of Pd-carbonaceous films obtained by two methods are presented in this paper.
The first method is PVD (Physical Vapour Deposition) with two separated sources containing precursors for films (1 -
fullerenes C60, 2- palladium acetate). The second method consists of two steps, the first step being PVD followed by
CVD (Chemical Vapour Deposition) - the second step. In the first step a nanocrystalline Pd-C film is prepared. Later this
film is used to obtain a nanoporous Pd - carbonaceous film in the CVD process. Prepared films contain 8 - 34 %wt. Pd.
Both kinds of films were studied using Raman and SEM methods. For the films obtained in the two-step method SEM
images show porous structure for all samples. Raman spectra for the film with 8 % wt. Pd exhibit C60 characteristic
bands, while Raman spectra for films with higher content of Pd show D and G graphite characteristic bands. Films
obtained by PVD are structurally different from films obtained by 2-steps method which is reflected in SEM images
where no porous structure has been found.
In this paper the method of structural and optical properties of novel crystals of the [N(C3H7)4]2MeBr4 (Me = Zn, Co, Cu)
will be presented. The X-ray investigations were carried out using four-circle diffractometer KM4-CCD at room
temperature Optical spectra of samples were measured using AVS-S2000 and 1725 FI -IR spectrometers. Connections
between optical properties of the studied crystals and electronic configuration of transition metal ions will be considered.
An influence of metal ion substitution on the shape of the optical spectra of crystals will be also discussed.
In this paper a concept of a non-contact method of temperature and humidity measurements based on the thermooptic and higroscopic effects of A2MX4 crystals is presented. Temperature and humidity influences on optical properties of some crystals were investigated. Possibilities of application of the A2MX4 crystals as a temperature and humidity sensors were discussed.
Interference images (figures) are the result of interference of light ray passing through anisotropy medium. In the case of ideal homogeneity structure, interference image is characterized by minimal influence of high-frequency spectrum coefficients. In the case of inhomogeneity of crystal structure a characteristic noise in the image is observed. In this paper, the schema of detecting process of crystal optical inhomogeneities based on wavelet transform of interference images is described. Some results of simulation of theoretically generated images are also presented.
Wavelet transform method is developed independently in the fields of mathematics, quantum physics, electrical engineering, and seismic geology from a several decades. The wavelets are mathematical functions that cut up data into different frequency components, and then study each component with a resolution matched to its scale. This method is more useful than traditional Fourier methods, when the signal contains discontinuities and sharp spikes. Interactions between different scientific fields have led to many new wavelet applications such as image compression, turbulence, human vision, radar, and earthquake prediction. This paper is dedicated to possibility of using the wavelet transform in some optical research method i.e. interference images analysis. Special attention is paid to noise detection in these images.
The results of optical investigations (absorption and transmission coefficients, optical density and reflection coefficient) for the crystals N(CH3)4ZnCl3 and [N(C2H5)4]2ZnCl4 are presented. The possibilities of application of these crystals in optoelectronics for digital recording are discussed.
The main features of crystals with incommensurate phases are reviewed. Special attention is paid to optical properties of ferroelectric crystals of the A2MX4 type. Some aspects of practical application of these materials in optoelectronics is also discussed.
Materials with non-linear properties such as thermal hysteresis of birefringence, electrooptic, thermooptic, piezooptic and thermochromic phenomena are very interesting both from scientific and practical points of view. They can be applied to photonic technology as optical memories, optical modulators, temperature and stress sensors. The examples of such materials are A2MX4 and AMX3 crystals (where A organic cation, M transition metal, X halogens). Possibilities and limitation of the A2MX4 and AMX3 crystals growth from water and organic solution have been discussed in order to determine the optimal parameters of the growth.
Photonics as other multidisciplinary fields needs a special educational approach. Our teaching innovation is based on the assumption that training the skill to solve problems in an independent way with the use of computer-assisted learning deepens the understanding of the subject. The advantages of such approach consist in the focus on significant aspects and the ability to rely on previously and newly acquired knowledge of different fields. In addition, students have the chance to practise technical presentation design with multimedia tools. Some examples of multimedia web techniques applications to the presentation of selected topics in Photonics education will be described.
The electro-optic effect in selected crystals of A2MX4 type is discussed. This effect, manifested in optical birefringence change under influence of external electric fields can be used in the construction of optical amplitude modulator.