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For many years there was a discrepancy between the theoretical and experimental capabilities in the design and manufacture of multilayer optical components. However, the increasingly complex market demands and the intensive development of nanoscience and nanotechnology during the last 15 years enabled the creation of highly complex thin film optical components. Thanks to the current state of the art it is possible to automate the production of optical thin film components that contain up to 2000 layers with a high level of precision and accuracy. Moreover, research of optical metamaterials and related technologies enabled the emergence of hybrid thin film optical components that can be produced only by using various technologies. Sometimes traditional multilayer systems, based on high- and low- refractive index is possible to replace with systems in which the refractive index almost continuously changes in accordance with the design, so we do not talk anymore about multilayer systems but rather about quasi-homogeneous monolayers. The current state of the art in the world, based on the recent own papers and some papers of other authors, will be presented. A foresight of the future developments in the area of optical coatings will be given.

A field with a high impact in nanoscience and nanotechnology today is plasmonics. The term plasmon refers to collective oscillations of conduction electrons in plasmonic materials, i.e. oscillations of charge density. Plasmonic effects are based on interaction processes between electromagnetic radiation and conduction electrons at metallic interfaces or in small metallic nanostructures, leading to an enhanced optical near field of sub-wavelength dimensions. Thus, it makes plasmonics a major part of the fascinating field of nanophotonics, which explores how electromagnetic fields can be confined within dimensions on the order of or smaller than the wavelength. In the focus of our research are nanoparticles of noble metals (silver, copper and gold) which, when illuminated by light, show unique optical properties due to the localized surface plasmon (LSP) resonance of free electrons. Besides detailed theoretical modelling of their plasmonic properties and interactions, we produce them in the form of metal island films (MIFs) which consist of metal nanoparticles deposited on a substrate upon evaporation in high vacuum. An overview of our research activities in this field over the last years is presented. Strong plasmonic absorption of noble MIFs at specific wavelengths depends on the particle size, shape, spatial distribution and dielectric environment, thus LSP properties of noble MIFs may be tailored by changing experimental parameters during sample preparation (amount of material, substrate temperature and deposition rate) or by changing dielectric environment around metal nanoparticles. Also, the LSP properties of noble MIFs can be tailored by post-deposition treatments (e.g. high-temperature annealing). Further tuning of the LSP resonance over a wide energy range can be obtained using bimetallic nanoparticles (e.g., gold-silver), either as core-shell or as alloyed structure. Due to this capacity of tailoring the optical properties, noble MIFs are interesting for various applications (e.g. novel approach to design of optical coatings). Finally the electric field assisted dissolution of metal nanoparticles (EFAD), owing to its simplicity and inexpensive technical requirements, represents an attractive possibility for production of low-cost plasmon-based two-dimensional and three-dimensional photonic structures.

Metal island films (MIF) are good candidates for sensors due to environment refractive index sensitive localized surface plasmon resonance. The strong near field enhancement in the vicinity of the island surface can be even higher if metal layer (ML) is placed close to MIF. Structures containing MIF with and without ML are prepared and sensitivities of spectrophotometric and ellipsometric features of measurements compared. It is shown that simple MIF is preferable for ellipsometric and including ML for spectrophotometric sensing

Structural investigation of Si nanoparticles embedded in oxide film

Typical representatives of plasmonic materials known in the form of thin fi lms are metal island fi lms of noble metals (gold, silver, copper). They are built as an almost planar arrangement of particles on the substrate. Due its specifi c resonant absorptive properties, caused by excitation of surface plasmons, they have recently triggered increased interest as novel constituents of specifi c optical multilayer designs. Their optical properties strongly depend on the embedding medium ; therefore the characterization of their properties is quite a challenging problem. Their morphology and optical properties are thickness dependent, which introduces additional complications in the design process. Finally, their optical properties depend on the coating technology applied which also has to be taken into consideration. Optical coaters prefer optical materials that have stable optical properties and all the above mentioned properties of plasmonic materials are not considered as preferable features. A review of the current state of the art, with practical examples for some special coatings applications will be presented. Feasibility to make sophisticated multilayers including plasmonic materials will be discussed. Finally, possible future applications of plasmonic materials in optical multilayers will be suggested.

Metal island fi lms of noble metals (silver, copper and gold) show unique optical properties due to the localized surface plasmon resonance of free electrons in metal nanoparticles. Strong plasmonic absorption at specifi c wavelengths, which depends on the particle size, shape, spatial distribution and dielectric environment, may be widely tailored varying production parameters. This makes these fi lms attractive for design of optical coatings beside usual dielectric layers. Noble metal island fi lms were produced using e-beam evaporation, embedded between diff erent combinations of TiO2 and/or SiO2 layers, on BK7 glass substrates. The tailoring of optical properties of the samples was done by changing mass thickness of deposited material and using diff erent dielectric layers above and below the metal island fi lm. The optical properties of noble metal island fi lms embedded between dielectric layers have been explored using effi cient procedure developed for optical characterization using spectroscopic ellipsometry. This procedure is based on modeling the dispersion of eff ective optical constants using a multiple oscillator approach. Thus obtained optical constants are prerequisite for implementation of noble metal island fi lms in the design of multilayer optical coatings for diff erent applications.

Thin metal island films (MIF) can show unusual optical phenomena such as near field enhancement, negative refraction and frequency selective absorption in the optical spectrum. All these effects are a consequence of the surface plasmon resonance (SPR). SPR is produced by coupling of the incoming electro-magnetic wave (light) into an evanescent surface wave of free electrons in the metal at the interface of the metal and dielectric. MIF can be made by the simple thermal evaporation process that can produce, either isolated, or clusters of metal nanoparticles with different morphological properties embedded in a dielectric matrix, depending on the deposition parameters (deposited mass of metal, substrate temperature, rate of deposition, etc.) [1]. Between such particles there is a large near field enhancement known as a "hot spot" (Fig. 1.) which is a result of a strong resonant process at the SPR and is very dependent on the shapes of such particles or islands. Such "hot spots" can be very useful for surface enhanced Raman spectroscopy (SERS) and various sensing applications [2]. Unfortunately, the geometrical shapes of such metallic nano-structures are usually very complex and therefore it is difficult to simulate their electro-magnetic behavior using classical Mie theory or similar analytical methods. One must use numerical algorithms such as FDTD (finite differences time domain) in order to get accurate results. The drawback of this method is a heavy computational load both on the computer resources and simulation time. In this work we study the effects of the mutual distance, size and shape on the field enhancement between two metal nano-particles using a FDTD numerical program. Results of this study are the first steps toward full wave simulations of large MIF on a dielectric substrate with a random distribution of positions, shapes and sizes of the islands. Such a simulation model would be very beneficial for optimization of the deposition process and could provide information on the near field of the MIF.

Copper, a common contaminant in semiconductors, was deposited onto unheated semi-insulating (SI) GaAs substrates by high vacuum e-beam method. SI GaAs:Cu, as well as referent undoped SI GaAs were annealed in the same manner, at various temperatures (Ta) in 300-800 K range. Cu diffused into SI GaAs and after each annealing step Thermally Stimulated Current (TSC), dark current (Idark) and photocurrent (Ipc) as well as its temperature dependence were measured and compared. At low annealing temperatures, in GaAs:Cu some TSC peaks, denoted by T1, T4a, T5 and T7, exceeded respective peaks from undoped SL GaAs for approximately 50%, while all other TSC peaks remained unchanged. In both materials at low Ta Idark was governed by the EL2 level, situated 0.75 +/- 0.02 eV below conduction band. For higher Ta in Cu doped sample TSC peaks gradually become dominated by Idark, which got governed by a relatively shallow level with activation energy of 0.15 eV. For annealing temperatures up to 720 K, Ipc (T) was very similar for doped and undoped samples. At higher Ta's, however, in SI GaAs:Cu Ipc decreased for more than four orders of magnitude, with characteristic fast quenching at 90 K. For even higher temperatures, SI GaAs:Cu became conductive. We concluded that Cu influenced some defects in SI GaAs and probably participates in their constitution.

All available commercial thin film design software use the model of homogeneous layers for doing the calculations. On the other hand, the real layers do rarely fully correspond to the theoretical model and very often their refractive indices are more or less non-homogeneous. This is especially noticeable at the substrate-film boundary where we usually have a refractive index gradient due the onset of the film's nucleation and growth. We used the reverse design to determine the refractive index profile for the monolayers made on the glass. Generally the problem of reverse design is a complicated one, but here the boundary conditions were pretty well known, and our extensive multilayer design experience was a deciding factor. Several popular optical materials like Al2O3, ZrO2 and HfO2 have been studied. Results have shown that the exact knowledge of the refractive index profile of the first layer on the glass is crucial for production of high quality antireflective coatings.

The effective dielectric function of metal-dielectric composites consisting of spherical particles randomly distributed in a matrix is numerically investigated. The study, based on the spectral density theory, shows that local field fluctuations may critically affect the composite performance for metamaterial applications. It appears that randomness significantly modifies the effective dielectric function of composites consisting of metal inclusions embedded in dielectric matrix. The effect is less remarkable for dielectric inclusions in a metal matrix.

Successful transfer of scientific results to the industrial use is the key for improvement of the competitiveness on the global market. Despite of numerous models of knowledge transfer, we are still faced with problems like “bridging the innovation gap” and similar. Various innovation systems have been developed at national levels but the problem of matching industrial needs with scientific expertise is still permanently present. To overcome that problem Croatian PROs and HEIs with support of European Union develop knowledge databases that should grow up to the national knowledge platform. It should enable the industry a direct access to scientific expertise and, therefore, act as a national brokering system. Of course the problem of tailoring the knowledge to the industrial needs will still exist, but it is expected that its common solving by partners will be much more straightforward and fruitful.

Metal dielectric composites have been in the focus of interest due to the surface plasmon resonance phenomena and its large number of related applications, ranging from biological and chemical sensing to telecommunications. Recently, novel photonic applications of metal-dielectric composites have been devised, in fields such as metamaterials operating in the optical range or wavelength-tunable superlenses. The key element is the possibility to broadly tailor the effective dielectric function of these composites, according to the predictions of effective medium theories. In the present work we study the effective dielectric function of Ag-SiO2 composites in thin film phase deposited by electron beam evaporation. The composites are obtained by the subsequent deposition of a small amount of Ag and SiO2 on a glass substrate. Due to the typical island-like growth of Ag on dielectrics, the metal film is composed of clusters of nanometric dimensions rather than being a compact film. The effective dielectric function of the resulting composite is determined by spectroscopic ellipsometry measurements. It is shown that by varying the substrate temperature only, the effective dielectric function of the composites can be widely modified. Composites deposited on heated substrates are characterized by a narrow localized surface plasmon absorption band, while those deposited at room temperature show a broader plasmon resonance and additional absorption in the infrared. This optical behavior can be associated with the growth of metal film either as isolated nearly spherical particles or to non-spherical particles with some degree of interconnectivity. The description of the effective dielectric function using classical effective medium theories fails and the experimental results can be explained only in the more general framework of the Bergman spectral density theory. Overall, the fabricated composites prove that a widely tunable effective dielectric function can be achieved by controlling the deposition temperature only. However, a correct quantitative modeling requires using advanced effective medium concepts.

U tankim filmovima pripravljenim magnetronskim rasprašenjem čest postoje velika unutrašnja naprezanja.

In this presentation we shall discuss motivation to study nanostructures and review our recent results obtained in collaboration between several groups. It is clear that properties of nanostructured materials give rise to enhanced properties of various devices. Therefore, it is of great importance to understand the basic properties of such materials. We believe that our expertise acquired in this filed will significantly contribute to the broad fund of knowledge that is a necessary prerequisite for a successful design and engineering of new generation of devices. We shall review several methods we are using to create nanostructures such as PVD on different substrates, magnetron sputtering of superlattices using different materials, and pulsed laser ablation in different atmospheres. We have shown that even macroscopic studies such as XRR provide a valuable information on self-assembly processes[1]. Another key question is self-organization. A full success of the superstructure method for the nanostructures formation is demonstrated although a lot of open questions remain in the spheres of structural decomposition, diffusion and self-assembly. It is clear that more detailed knowledge on the interplay of defects and self-assembly process is required. It will be shown that in specific cases a high degree of self-assembly can be obtained which means that an expensive lithography steps in processing could be avoided[2]. Further details on structural. optical and electric properties will be presented and discussed. [1] I. Kovačević, B. Pivac, P. Dubček, H. Zorc, N. Radić, S. Bernstorff, M. Campione, and A. Sassella, Appl. Surf. Sci., 253, 3034-3040 (2007). [2] B. Pivac, P. Dubček, I. Capan, I. Zulim, T. Betti, H. Zorc, S. Bernstorff, J. Nanosci. Nanotechnol., 9, 3853-3857 (2009). [3] M. Buljan, U.V. Desnica, M. Ivanda, N. Radić, P. Dubček, G. Dražić, K. Salamon, S. Bernstorff, V. Holy, Physical Review B, 79 (2009) , 3 ; 035310-035321.

Silicijevi oksidi su vrlo koristan materijal u mikroelektronici i optoelektronici zbog mogućnosti mijenjanja električnog otpora i optičkih osobina promjenom stehiometrije. Pri tome se SiOx

Metalne čestice dimenzija mnogo manjih od valne duljine ponašaju se kao točkasti dipoli pri čemu je plazmon posljedica kolektivnih oscilacija slobodnih elektrona u metalnoj čestici. Istraživane su optičke karakteristike nanočestica plemenitih metala. Pri tome je težište bilo na modeliranju plazmonskih svojstava kako čestica na površini tako i onih koje su uklopljene u dielektričnu matricu. Određen je pomak rezonantne frekvencije koji ovisi o veličini nanočestica, oblik i raspodjela nanočestica, i drugi parametri relevantni za formiranje optičkih svojstava. Istražene su primarno nanočestice zlata i srebra, no započeto je i istraživanje nanočestica bakra. Za karakterizaciju su korištene metode spektroskopije, AFM, GISAXS, WAXS i druge. Rezultati su ukazali na zanimljive mogućnosti kombinacije metalnih nanočestica i dielektričnih materijala, od kojih se mogu očekivati inovativne optičke komponente za razne namjene.

Very high internal stresses (sometimes about few GPa in compression) are often developed in thin films and coatings produced by sputtering methods. Those are then susceptible to delamination and buckling, which is undesirable for future technological applications, but this phenomenon can be used for characterization of mechanical properties of both films and substrates. In order to examine the effects of magnetron deposition parameters (working gas pressure, depositon rate) and film thickness upon the onset of the macroscopic structural defects, a series of tungsten-films-on-glass samples were prepared. The effect of aluminum buffer layer has been checked, as well. A geometry of developed buckling structures (straight-side wrinkles, telephone cord buckles) was determined by microscopic observations, while topography has been measured by profilometar. Using the geometrical analysis of buckling structures and elastic theory we were able to calculate mechanical stress in thin tungsten film and compare the result to the values obtained by profilometry and XRD measurements.

Metal islands films (MIFs) of Ag on glass substrates were fabricated by the e-beam evaporation process. The dependence of the surface plasmon (SP) absorption wavelength on the deposition mass thickness and substrate temperature was quantified. The structural and optical characterization of the MIFs, done by spectrometry, grazing incidence small angle X-ray scattering (GISAXS) and atomic force microscopy (AFM) evidences that the evolution of SP characteristics with the fabrication parameters: red-shift of the absorption peaks with the increase of deposition thickness accompanied by peak widening and the blue-shift of peaks with the increase of deposition temperature followed by the peak narrowing. These findings were explained by the differences in the concentration, shape and size of the obtained silver islands.

We present a study on amorphous SiO/SiO2 superlattice formation on Si substrate held at different elevated temperatures.

The growth of the self-organization of Ge nanostructures on Si substrate have been extensively studied.

Metal island films show unique optical properties owing to the local surface plasmon resonance of islands free electrons. In the present study, the electric field assisted dissolution of clusters in metal island films is reported. Island films of Au, Ag, and Cu are deposited under different conditions by thermal evaporation and coated with thin dielectric layers. The samples are treated with the simultaneous application of an intense electric field and temperature, leading to the sample partial or total bleaching due to the dissolution of metal clusters in the films. Owing the facility of production of metal island films and the inexpensive technical requirements of the dissolution process, this approach suggests a novel path for the production of low-cost photonic structures.

One approach for silicon based next generation solar cells relies on the production of suitable Si nanostructured objects in wide bandgap material. Present research on Si nanosize structures is focused on the Si nanocrystals prepared by sputtering or physical vapor deposition of Si rich oxides and SiO2 multilayers on Si substrates. We present a study on amorphous SiO/SiO2 superlattice formation on Si substrate held at different elevated temperatures. Grazing-incidence small-angle X-ray scattering (GISAXS), X-ray reflectivity and photoluminescence were used to study such samples. From the 2D GISAXS pattern it is possible to determine the shape, size and inter-particle distance. Amorphous SiO/SiO2 superlattices were prepared by magnetron sputtering of 2nm thin films of SiO and SiO2 (10 layers each) from corresponding targets on silicon substrate. Rotation of the Si substrate during evaporation enables homogeneity of films over the whole substrate. After evaporation samples were annealed at 1050  C in different atmospheres. The analysis of the 2D GISAXS pattern has shown that Si nanocrystals are already present in the samples deposited at elevated temperatures. Using a Guinier approximation, the inter-nanocrystal distance and the thickness of the nanocrystals have been obtained. A long range ordering of nanocrystals deposited at elevated temperatures is observed.

Metal islands films (MIFs) of Ag on glass substrates were fabricated by the e-beam evaporation process. The dependence of the surface plasmon (SP) absorption wavelength on the deposition mass thickness and substrate temperature was quantified. The structural and optical characterization of the MIFs, done by spectrometry, grazing incidence small angle X-ray scattering (GISAXS) and atomic force microscopy (AFM) evidences that the evolution of SP characteristics with the fabrication parameters: red-shift of the absorption peaks with the increase of deposition thickness accompanied by peak widening and the blue-shift of peaks with the increase of deposition temperature followed by the peak narrowing. These findings were explained by the differences in the concentration, shape and size of the obtained silver islands.

Recently, Si and Ge nanocrystals (ncs) embedded in a silicon dioxide (SiO2) matrix have been widely studied for their luminescence and charge retention properties for integration as opto-electronic and microelectronic devices in complementary metal-oxide-semiconductor (CMOS) technology. As far as memories are concerned, a nc-layer located at a tunneling distance from the Si/SiO2 interface can be used as a floating gate in order to reduce the lateral charge loss limiting conventional flash memories. Samples were prepared by high-vacuum evaporation of a 3 nm thick tunneling SiO2 layer on a n-type silicon substrate with resistivity 10-50  cm, followed by evaporation of a 6 nm thick SiO layer. On top, a 20 nm control oxide was deposited. Upon subsequent thermal annealing in vacuum, Si ncs are formed. The structural properties of the Si ncs are studied by means of grazing incidence small and wide angle x-ray scattering. It is shown that Si nanostructures are formed which crystallinity, size and morphology depends on the annealing temperature. Aluminum electrodes for the front and back sides were evaporated, in order to investigate the charge retention of the samples by means of capacitance-voltage (CV) measurements.

One approach for silicon based next genration solar cells relies the production of suitable Si nanostructured objects in wide bandgap material. Present research on Si nanosize structures is focused on the Si nanocrystals prepared by sputtering of Si rich oxides and SiO2 multilayers on Si substrates. We present a study on amorphous SiO/SiO2 superlattice formation on Si substrate held at different elevated temperatures. Grazing-incidence small-angle X-ray scattering (GISAXS), X-ray reflectivity and photoluminescence were used to study such samples. From the 2D GISAXS pattern it is possible to determine the shape, size and inter-particle distance. Amorphous SiO/SiO2 superlattices were prepared by magnetron sputtering of 2nm thin films of SiO and SiO2 (10 layers each) from corresponding targets on silicon substrate. Rotation of the Si substrate during evaporation enables homogeneity of films over the whole substrate. After evaporation samples were annealed at 1050  C in different atmospheres. The analysis of the 2D GISAXS pattern has shown that some Si nanocrystals are already present in some samples deposited at elevated temperatures. Using a Guinier approximation, the inter-nanocrystal distance and the thickness of the nanocrystals have been obtained. A long range ordering of nanoparticles deposited at elevated temperatures are observed.

U radu se opisuje proces integracije hrvatske znanosti u Europski istraživački prostor. Posebno se spominju izazovi koji predstoje kako u financiranju znanosti tako u modifikaciji znanstvene politike te o koracima koje bi trebali poduzeti ključni čimbenici.

One approach for silicon based next genration solar cells relies the production of suitable Si nanostructured objects in wide bandgap material. Present research on Si nanosize structures is focused on the Si nanocrystals prepared by sputtering of Si rich oxides and SiO2 multilayers on Si substrates. We present a study on amorphous SiO/SiO2 superlattice formation on Si substrate held at different elevated temperatures. Grazing-incidence small-angle X-ray scattering (GISAXS), X-ray reflectivity and photoluminescence were used to study such samples. From the 2D GISAXS pattern it is possible to determine the shape, size and inter-particle distance. Amorphous SiO/SiO2 superlattices were prepared by magnetron sputtering or high vacuum evaporation of 2nm thin films of SiO and SiO2 (10 layers each) from corresponding targets on silicon substrate. Rotation of the Si substrate during evaporation enables homogeneity of films over the whole substrate. After evaporation samples were annealed at 1050 C in different atmospheres. The analysis of the 2D GISAXS pattern has shown that some Si nanocrystals are already present in some samples deposited at elevated temperatures. Using a Guinier approximation, the inter-nanocrystal distance and the thickness of the nanocrystals have been obtained. A long range ordering of nanoparticles deposited at elevated temperatures are observed.

Recently, Si and Ge nanocrystals (ncs) embedded in a silicon dioxide (SiO2) matrix have been widely studied for their luminescence and charge retention properties for integration as opto-electronic and microelectronic devices in complementary metal-oxide-semiconductor (CMOS) technology. As far as memories are concerned, a nc-layer located at a tunneling distance from the Si/SiO2 interface can be used as a floating gate in order to reduce the lateral charge loss limiting conventional flash memories. Samples were prepared by high-vacuum evaporation of a 3 nm thick tunneling SiO2 layer on a n-type silicon substrate with resistivity 10-50  cm, followed by evaporation of a 6 nm thick SiO layer. On top, a 20 nm control oxide was deposited. Upon subsequent thermal annealing in vacuum, Si ncs are formed. The structural properties of the Si ncs are studied by means of grazing incidence small and wide angle x-ray scattering. It is shown that Si nanostructures are formed which crystallinity, size and morphology depends on the annealing temperature. Aluminum electrodes for the front and back sides were evaporated, in order to investigate the charge retention of the samples by means of capacitance-voltage (CV) measurements.

Photodynamic therapy (PDT) mediated by 5-aminolevulinic acid (ALA) has been introduced as a new anticancer therapeutic modalities. In January 2004, we have started topical PDT in the treatment selected group of patients with epidermal precancerous and cancerous lesions. Lesions were treated by topical application of 20% 5-ALA dissolved a proprietary oil-in- water emulsion. The ALA containing emulsion was applied under occlusive dressing 5-6 hours before illumination with non-coherent red light (630-700 nm, light dose 100-150 J/cm2). Prior to therapy diagnostics has been done using MEDILED-5 device. In our study 50 patients were included (twenty four men and twenty six women). Twenty patients had superficial basal cell carcinoma, eleven patients had other types of basal cell carcinoma, eleven had Bowen's disease and eight patients had other precancerous and cancerous lesions. Nine patients had recurrences after surgical excision and/or radiotherapy. In most patients complete or partial regression was achieved after one to three treatments. PDT is an alternative modality to surgical excision or superficial radiotherapy. This is also a good option for the treatment of recurrences after surgical treatment and superficial radiotherapy.

Fotodinamička terapija (PDT) i fotodinamička dijagnostika (PDD) nove su metode koje se primjenjuju u liječenju određenih vrsta kožnih karcinoma, nekih drugih kožnih bolesti, te bolesti određenih unutarnjih organa. Za pobudu fotoosjetljivih tvari u bolesnim stanicama i njihov raspad pri međudjelovanju sa svjetlom, što je osnovno načelo metode, u PDT-u i PDD-u primjenjuju se izvori svjetlosti određenih valnih duljina i jakosti. Valne duljine izvora ovise o apsorcijskim karakteristikama fotoosjetljive tvari. Za aminolevuliničku kiselinu (5-ALA) u PDD-u primjenjuje se ljubičasta svjetlost, a detektira se crvena svjetlost. U PDT-u se primjenjuje crvena svjetlost. U PDD-u je potrebno odvojiti (filtrirati) uzbudni dio spektra od fluorescencije protoporfirina IX(PpIX). Za dodatnu zaštitu pacijenata i terapeuta tijekom PDD-a i PDT-a potrebno je filtrirati svjetlo u UV i u crvenom području spektra.Osnovni fizikalni problem bio je dizajn i izvedba odgovarajućih interferencijskih filtara. Dizajn filtara izveden je uz pomoć komercijalnih računalnih programa, a izradba depozicijom višeslojnih sustava dielektričnih materijala (TiO2 i SiO2). Učinjena je i karakterizacija filtara koja je potvrdila da dobiveni filtri u potpunosti odgovaraju postavljenim zahtjevima. Photodynainic therapy (PDT) and photodynamic diagnosis (PDD) are new methods in treatment of certain skin carcinoma, some other skin diseases as well as in treatments of some other internal organ carcinoma. The combination of photosensitizing drug and light, in the presence of molecular oxygene is used to obtain a therapeutic and diagnostic effects. The wavelength and intensity of the light depend on the photosensitiser used. For aminolevulinic acid (5-ALA), in PDD violet light is used while red light is detected. In PDT red light is used. In PDD the separation of excitation and absorption is needed. For additional protection of patients and therapeuts it is necessary to filtrate the light in UV and red parts of spectrum. The basic problem has been to design and produce interference filters which fulfill the above conditions. The design has been made by comercial computer programs which resulted by deposition of filters composed of multileyers of dielectric oxide materials (TiO2 and SiO2). Produced filters have been characterized and it is confirmed that they fulfill all wanted properties.

Photodynamic diagnostics of skin tumors is based on the visualization of fluorophores, which accumulate in tumor tissue, by use of fluorescence imaging. Of particular importance is application of  -5-aminolaevulinic acid (ALA) that stimulates formation of protoporphyrin IX (Pp IX) through the process of biosynthesis. Higher concentration of Pp IX in tumor tissue, compared to surrounding healthy skin, is the basis for PDD. The study has been done on a patient suffering from Basal Cell Carcinoma (BCC) treated with ALA. Our contribution in this communication is twofold. First, we have compared performance of four fluorescence excitations in term of the quality of BCC localization. We have used the following excitation sources: 405 nm lamp (MEDILED-5), the Wood’ s lamp, the MEDILED-5 and Wood’ s lamp together and the filtered photo flash lamp. We have demonstrated that fluorescent image obtained using excitation with MEDILED-5 lamp is the most consistent in term of the quality of BCC localization. Second, we have compared three methods used for the processing of fluorescent BCC images in order to obtain the BCC spatial maps. The following three image processing methods have been applied: the ratio imaging, optimal threshold and independent component analysis (ICA). The ratio image is obtained by calculating ratio between red and green component for every pixel. The optimal threshold image is obtained by classifying as a BCC everything that is above 1.4Ia, where Ia represents average intensity of the region with healthy skin. We have demonstrated that BCC spatial map produced by ICA is most consistent in term of the quality of BCC localization.

Topical photodynamic therapy (PDT) is a highly effective treatment for several skin tumors as Actinic Keratoses, Bowen's Disease, Superficial Basal Cell Carcinoma and other pre-malignant diseases. Treatment is well tolerated and can be performed on outpatient basis. In one-year period on Outpatient department of dermatology, 20 patients were treated with topical PDT. The light source was MEDILED-4 PDD & PDT system. Biopsies were performed prior and one month after the PDT treatment. Indications were solely actinic keratosis and Bowen's disease. One group of patients (four women and six males) was PDT treated 4 hours after administration of 20% 5-aminolaevulinic acid cream (ALA). The delivered light dose of 75 J/cm2 resulted in low clearance rates what was confirmed by histopathological findings. The second group of patients (two women and eight males) was treated with PDT 16 hours after 5-ALA administration. The total illumination dose was 100 J/cm2 with interruption of 30 minutes after received 50 J/cm2. The latter protocol showed much higher efficiency in tumors' eradication and all patients in our clinics are now being successfully treated using the new protocol.

Fotodinamička terapija (PDT) i fotodinamička dijagnostika (PDD) nove su metode koje se primjenjuju u liječenju određenih vrsta kožnih karcinoma, nekih drugih kožnih bolesti, te bolesti određenih unutarnjih organa. Za pobudu fotoosjetljivih tvari u bolesnim stanicama i njihov raspad pri međudjelovanju sa svjetlom, što je osnovno načelo metode, u PDT-u i PDD-u primjenjuju se izvori svjetlosti određenih valnih duljina i jakosti. Valne duljine izvora ovise o apsorcijskim karakteristikama fotoosjetljive tvari. Za aminolevuliničku kiselinu (5-ALA) u PDD-u primjenjuje se ljubičasta svjetlost, a detektira se crvena svjetlost. U PDT-u se primjenjuje crvena svjetlost. U PDD-u je potrebno odvojiti (filtrirati) uzbudni dio spektra od fluorescencije protoporfirina IX(PpIX). Za dodatnu zaštitu pacijenata i terapeuta tijekom PDD-a i PDT-a potrebno je filtrirati svjetlo u UV i u crvenom području spektra.Osnovni fizikalni problem bio je dizajn i izvedba odgovarajućih interferencijskih filtara. Dizajn filtara izveden je uz pomoć komercijalnih računalnih programa, a izradba depozicijom višeslojnih sustava dielektričnih materijala (TiO2 i SiO2). Učinjena je i karakterizacija filtara koja je potvrdila da dobiveni filtri u potpunosti odgovaraju postavljenim zahtjevima.

In this apper we present a study of annealing effects on amorphous SiO/SiO2 superlattice using grazing-incidence small-angle X-ray scattering (GISAXS).

During the last few years, refractive index profiles are being studied more intensively. Several papers have been written about the use of optical methods, spectrophotometry, ellipsometry, together with reverse engineering, these have yielded interesting results. Here we study the differences of a ZrO2 film grown on an amorphous substrate and that of a pre-evaporated layer of another material, Y2O3. In the first run, two glass substrates have been coated with an Y2O3 layer. In the second run a bare glass substrate and the pre-coated Y2O3 have been coated with a ZrO2 layer. Each of the materials used had exactly the same growth conditions for all layers. The only difference was the nature of substrates. The spectra of R and T of both samples have been used for the optical characterisation. Multisample analysis with gradual introduction of new parameters has been carried out. It was found that for the appropriate modelling of the layer, grown on the pre-coated substrate, introduction of an interface layer between the two materials was necessary. The refractive index profiles of both ZrO2 layers have been determined and discussed.

Germanium islands, were formed on (100) oriented single-crystal silicon sub-strates by subsequent annealing of the evaporated film, and by magnetron sputtering of Ge on the substrate held at elevated temperatures. The struc-tures formed by these processes have been studied by grazing incidence small angle X-ray scattering (GISAXS) and by atomic force microscopy (AFM). A series of samples, annealed isothermally for different periods of time have been prepared and the island growth dynamics has been studied. Particle like scattering is evident already in as prepared sample though imbedded in the dominant thin film signal. The annealing leads first to the film re-laxation and ordering, as evidenced by the enhancement of the fringes for the shorter annealing times. The prolonged annealing affects first the upper surface roughness, and finally leads to the full particles formation. The mor-phology of the particles was analyzed by AFM and compared to the results obtained by GISAXS analysis.

We present a preliminary study of Ge islands formation on Si(100) substrates using grazing-incidence small-angle X-ray scattering (GISAXS). Samples were prepared by a high-vacuum evaporation of a 5nm thick Ge layer on Si(100) substrate held at 200  C. The samples were subsequently annealed at different temperatures for 1h in vacuum, yielding to island formation. A Fortran program IsGISAXS was used for the simulation and analysis of Ge islands. Vertical cut (perpendicular to the surface) of the experimental 2D GISAXS pattern has been fitted using a Guinier approximation. Obtained parameters were used for the simulations. The simulated 2D GISAXS pattern well reproduce experimental data for cylindrically shaped islands with morphological parameters R=4 nm, H/R= 0.25 and the average inter-island distance D=5 nm.

The recent fast developments of new LED light sources enabled design of a new source for photodynamic diagnostics and therapy. Based on LED clusters of carefully tuned wavelengths, it is possible to minimize the heat ballast to tissue and, therefore, obtain a better control over the processes during the diagnostics and therapy. Three types of LED clusters provide white light, violet light (405 nm) and red light (635 nm) for the photography, PDD and PDT, respectively. For the needs in the process of clinical research the bleaching of ALA-PPIX during the therapy can be followed very easily using a built-in TV camera. The sources have been applied to PDD and PDT of Mycosis Fungoides but all other non-melanoma cancers can be treated very successfully. Adjustment to different power densities for the therapy, in order to adjust the pain threshold, can be done very easily. According the known facts of development of Mycosis Fungoides, it has been found that sources yield a highly successful therapy which significantly improves the quality of life of patients.