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The quantum efficiency and the molar-absorption coefficients of different phenothiazine dyes are obtained by means of fitting the experimental data of transmittance as a function of time. An analytical expression for the intensity transmitted in a photopolymerizable holographic material is obtained, and good agreement between theory and experience is also achieved. The analysis of these parameters is of fundamental quantities in the photochemical characterization of holographic recording materials.

A study of the optimization and the characteristics of a dry film photopolymerizable recording material is presented. The effects of intensity, the thickness, and the variation of the concentration of each component have been studied. Diffraction efficiencies of 80%, with energetic sensitivities of 40 mJ/cm(2), have been obtained in photosensitive films of a 35-mum thickness with a spatial frequency of 1000 lines/mm.

We theoretically analyze Airy beams by solving the exact vectorial Helmholtz equation using boundary conditions at a diffraction aperture. As result, the diffracted beams are obtained in the whole space; thus, we demonstrate that the parabolic trajectories are larger than those previously reported, showing that the Airy beams start to form before the Fourier plane. We also demonstrate the possibility of using a new type of Airy beams (SAiry beams) with finite energy that can be generated at the focal plane of the lens due to diffraction by a circular aperture of a spherical wave modified by a cubic phase. The finite energy ensured by the principle of conservation of energy of a diffracted beam.

Combined chemo and photothermal therapy in in vitro testing has been achieved by means of multifunctional nanoparticles formed by plasmonic gold nanoclusters with a protecting shell of porous silica that contains an antitumor drug. We propose a therapeutic nanoplatform that associates the optical activity of small gold nanoparticles aggregates with the cytotoxic activity of 20(S)-camptothecin simultaneously released for the efficient destruction of cancer cells. For this purpose, a method was used for the controlled assembly of gold nanoparticles into stable clusters with a tailored absorption cross-section in the vis/NIR spectrum, which involves aggregation in alkaline medium of 15 nm diameter gold colloids protected with a thin silica layer. Clusters were further encapsulated in an ordered homogeneous mesoporous silica coating that provides biocompatibility and stability in physiological fluids. After internalization in 42-MG-BA human glioma cells, these protected gold nanoclusters were able to produce effective photothermolysis under femtosecond pulse laser irradiation of 790 nm. Cell death occurred by combination of a thermal mechanism and mechanical disruption of the membrane cell due to induced generation of micrometer-scale bubbles by vaporizing the water inside the channels of the mesoporous silica coating. Moreover, the incorporation of 20(S)-camptothecin within the pores of the external shell, which was released during the process, provoked significant cell death increase. This therapeutic model could be of interest for application in the treatment and suppression of non-solid tumors.

A photopolymerizable holographic material has been obtained and characterized using agent N,N′-dihydroxiethylenbisacrylamide as crosslinking. A sensitivity of 5 mJ/cm2 and a diffraction efficiency around of 70% have been reached for holograms recorded at 633 nm with a spatial frequency of 1000 lines/mm. High sensitivities can be obtained with low intensities, and this is important in applications such as holographic interferometry and the fabrication of holographic optical elements.

We present theoretical results for angular responses of transmitted and diffracted beams in mixed amplitude -phase holographic gratings. Experimental results for gratings recorded in photographic emulsions and developed without a bleaching bath, with diffraction efficiencies of .20%, are also presented. The model shows an angular shift between minimum transmittance and maximum diffraction efficiency when both index modulation and absorption coefficient modulation are present. Also, the Borrmann effect was found outside the Bragg angle. This method can be extended to a study of the mechanism of image formation in materials such as bacteriorhodopsin and azo-dye-doped polymers that exhibit both types of modulations (index and absorption).

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