ABSTRACT
Optical properties of metal island films (MIFs) can be combined with interference of dielectric coatings. A set of multilayer designs containing metal clusters reflecting different colours from front and back side of the coating was obtained by numerical optimization. The chosen designs presenting the range of feasible colours were deposited by electron beam evaporation. Spectrophotometric and ellipsometric measurements verified that the produced coatings present an excellent agreement with the optical performance calculated from the designs. Numerical optimization was verified as a useful method in designing of coatings containing MIFs. This approach can ease the implementation of metal clusters into multilayer designs and broaden the applications of MIFs.
Subject(s)
Color , Gold/chemistry , Membranes, Artificial , Photometry/methods , Surface Plasmon Resonance/methods , Materials TestingABSTRACT
We present a study on amorphous SiO/SiO2 superlattice formation on Si substrate held at room temperature and annealed in the temperature range 600-1100 degrees C. Grazing-incidence small-angle X-ray scattering (GISAXS) and X-ray reflectivity were used to study such samples. Amorphous SiO/SiO2 superlattices were prepared by high vacuum physical vapor deposition of 4 nm thin films of SiO and SiO2 (10 layers each) from corresponding targets on silicon substrate. Rotation of the Si substrate during evaporation ensured homogeneity of the films over the whole substrate. We observed that the inhomogeneities introduced into the SiO and SiO2 layers during the deposition (evaporation) give rise to small angle scattering at lower annealing temperatures. After an initial SiO layer thickness reduction for 600 degrees C annealing, these thicknesses remain virtually unchanged up to 1000 degrees C, where they start to decrease again which leads to particle formation. Nevertheless, this compacting at low temperatures may lead to the seed formation in SiO layers that will facilitate later Si nanoparticles growth.
ABSTRACT
A class of problem dealing with narrow-band reflectors under oblique light incidence has been selected, and a group of design procedures leading to satisfactory results is analyzed. Initially performance criteria and design restrictions are set. Various designs are then created and analyzed. Conclusions can then be drawn on the relative merits of the designs. Two different types of target function have been chosen. A global search for 50 or more layers with varied optical thicknesses between 0 and lambda/2 and a needle design method have been applied to the synthesis. Gradient and variable metrics have been used for further refinement. Results are compared, and it is shown that all the design methods used yield similar results for this problem. The issue of how to determine the best method is addressed.
ABSTRACT
The role of physical parameters such as light intensity, irradiation time, light wave-length and photoactive substance concentration during photodynamic therapy is discussed. Optimal values for all these parameters were determined in a well defined biological model based on the treatment of CMC-2 fibrosarcoma implanted in the right hind leg of CBA/HZgr mice.
Subject(s)
Antineoplastic Agents/administration & dosage , Dihematoporphyrin Ether/administration & dosage , Fibrosarcoma/drug therapy , Photochemotherapy , Animals , Light , Mice , Mice, Inbred CBA , Neoplasm Transplantation , Radiation Dosage , Time FactorsABSTRACT
The effect of different local temperature increase in normal and tumorous tissue, influenced by red light commonly used in photodynamic therapy, on tumor growth rate was reanalyzed, taking into account the tumor tissue penetration depth of the light used. The rear part of the tumor is definitely not receiving the same light dose, and consequently the same amount of heat energy, as the front part. The effect is taken into account by using a mathematical model of tumor growth for the rear part of the tumor. Positive experimental results of hyperthermia due to the energy deposited by the red light, are more encouraging after such a correction than previously reported.
