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.
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.
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.
We present results of Raman studies of CNT-Ni films obtained in two steps method. In the first step an initial
nanocomposite Ni-C film (produced by PVD method) was prepared. This initial film has multiphase composite-like
structure with nanograins of fullerenes, amorphous carbon and nickel. In the second step CNTs were obtained by CVD
method. In this process the initial films were placed in a quartz tube reactor where pyrolysis process were performed in
xylene. Decomposition of xylene at 650°C was occurred. Products of this CVD decomposition process take part in
nanotubes growth on Ni nanograins. These nanograins play a role of a catalyser of the growth process. SEM
observations showed that form of nanotubes obtained with the various CVD process parameters is similar.
Raman studies of initial films (obtained PVD process) confirm the presence of fullerenes C<sub>60</sub> in and some forms of
graphite–like objects in the samples. Raman spectra of MWCNTs films contained: bands characteristic for carbon
In the studies presented we proposed a new application for nanocomposite carbon films (C-Pd). These films were
evaluated as an anode material for Microbial Fuel Cells (MFCs) used for electrical current generation. The results of
characterization of C-Pd films composed of carbon and palladium nanograins were obtained using the Physical Vapor
Deposition (PVD) method. The film obtained by this method exhibits a multiphase structure composed of fullerene
nanograins, amorphous carbon and palladium nanocrystals. Raman Spectroscopy (RS) and scanning electron microscopy
(SEM) are used to characterize the chemical composition, morphology and topography of these films.
We observed, for MFC with C-Pd anode, the highest electrochemical activity and maximal voltage density - 458 mV
(20,8 mV/cm<sup>2</sup>) for Proteus mirabilis, 426 mV (19,4 mV/cm<sup>2</sup>) for <i>Pseudomonas aeruginosa</i> and 652 mV (29,6 mV/cm<sup>2</sup>)
for sewage bacteria as the microbial catalyst.
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 H<sub>2</sub>/N<sub>2</sub> 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 H<sub>2</sub> in interaction with C-Pd film needs other experimental works. Observed phenomenon can
be used in construction of optical hydrogen sensor.
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.
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 C<sub>60</sub>, 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(C<sub>3</sub>H<sub>7</sub>)<sub>4</sub>]<sub>2</sub>MeBr<sub>4</sub> (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.
The paper presents preparation of film composed of Pd nanocrystals embedded in carbonaceous matrix and
characterization of their characteristics, such as structure and optical properties. Pd nanocrystalline films were obtained
by the physical vacuum deposition method (PVD) and were studied by TEM, AFM and optical absorption (UV-VIS
absorption) methods. Pd nanocrystals have structure of fcc type and are embedded in matrix based on fullerene structure
of fcc type. The interaction between Pd and elements of carbon matrix interface were studied by UV-VIS absorption
The characterization Ni<sub>N</sub> nanocrystals (N- number of atoms in a nanocrystal) embedded in carbonaceous matrices is presented. The physical vapor deposition method was used to prepare nanocrystals. Transmission electron microscopy (TEM), atomic force microscopy (AFM), chemical analysis methods and optical absorption spectroscopy have been used to study samples properties. A hypothetical structure of nanocrystals Ni<sub>N</sub> (13<N<200) will be discussed.
In this paper a concept of a non-contact method of temperature and humidity measurements based on the thermooptic and higroscopic effects of A<sub>2</sub>MX<sub>4</sub> crystals is presented. Temperature and humidity influences on optical properties of some crystals were investigated. Possibilities of application of the A<sub>2</sub>MX<sub>4</sub> 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(CH<sub>3</sub>)<sub>4</sub>ZnCl<sub>3</sub> and [N(C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>]<sub>2</sub>ZnCl<sub>4</sub> are presented. The possibilities of application of these crystals in optoelectronics for digital recording are discussed.
The deep learning in Optics can be encouraged by stimulating and considerate teaching. It means that teacher should demonstrate his/her personal commitment to the subject and stress its meaning, relevance and importance to the students. It is also important to allow students to be creative in solving problems and in interpretation of its contents. In order to help the students to become more creative persons it is necessary to enhance the learning process of modern knowledge in Optics, to design and conduct experiments, stimulate passions and interests, allow an access to the e-learning system (Internet) and introduce the psychological training (creativity, communication, lateral thinking etc.) (<i>Abstract only available</i>)
The main features of crystals with incommensurate phases are reviewed. Special attention is paid to optical properties of ferroelectric crystals of the A<sub>2</sub>MX<sub>4</sub> 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 A<sub>2</sub>MX<sub>4</sub> and AMX<sub>3</sub> crystals (where A organic cation, M transition metal, X halogens). Possibilities and limitation of the A<sub>2</sub>MX<sub>4</sub> and AMX<sub>3</sub> 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 A<sub>2</sub>MX<sub>4</sub> 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.