Photoinduced electrooptics in the In2O3 nanocrystals incorporated into PMMA matrixes

We have observed an appearance of clear morphological structure in composites containing In2O3 nanocrystals (NCs) incorporated into polymethyl methacrylite (PMMA) matrices under optical treatment by a polarized femtosecond laser. The initial photoinduced treatment was carried out using a Ti:sapphire femtosecond laser emitting 140 fs p-polarized light at a maximum spectral wavelength 775 nm with pulse repetition 1 kHz. It was found that the average morphological radius is varied maximally only during illumination at liquid helium temperature (T = 4.2 K). The morphological average mean radius is strictly dependent on the sizes of incorporated In2O3 NCs. Afterwards we measured the linear electrooptic effect at cw He–Ne laser wavelength 633 nm during simultaneous treatment by 1060 and 530 nm coherent beams of a Nd–YAG picosecond laser. We have established that a decrease of the average morphological mean radius favours an increase of the optically poled linear electrooptic coefficient. The diameters of In2O3 NCs were evaluated using transmission electron microscopy (TEM) and light-scattering techniques, whereas the NC sizes and morphological average mean radius of formed nanocomposites were estimated by atomic force microscopy (AFM). A relationship between the diameter of the NC, composite morphological mean average radius and effective linear electrooptic coefficient was established.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58122/2/cm7_1_016204.pd

Picosecond nonlinear optical features of ferroelectric A(6)M(2)M(8)O-30 large sized nanocrystallites

Second and third order nonlinear optical susceptibilities of A(6)M(2)M(8)O-30 ferroelectric crystallites 100 nm powders were studied. The measurements were carried out for powders and thin films of guest-host composites made of Poly(methyl methacrylate) (PMMA) matrix. The studies were carried out by Kurtz Perry method using a Q-switch 16 ps picosecond Nd:YAG laser with peak pulse power 25 MW operating at 1064 nm fundamental wavelength. We have established that Ba6Ti2Nb8O30 ferroelectric crystallites achieve the highest (among the studied materials) second order optical susceptibilities equal to about 8.12 pm/V. The use of picosecond laser pulses and of the crystallites with high monodispersion allow to obtain an information concerning the second order optical susceptibilities with the avoiding of the local thermoheating which may change the output susceptibilities

Optical second harmonic generation in Yttrium Aluminum Borate single crystals (theoretical simulation and experiment)

Experimental measurements of the second order susceptibilities for the second harmonic generation are reported for YAl3(BO3)4 (YAB) single crystals for the two principal tensor components xyz and yyy. First principles calculation of the linear and nonlinear optical susceptibilities for Yttrium Aluminum Borate YAl3(BO3)4 (YAB) crystal have been carried out within a framework of the full-potential linear augmented plane wave (FP-LAPW) method. Our calculations show a large anisotropy of the linear and nonlinear optical susceptibilities. The observed dependences of the second order susceptibilities for the static frequency limit and for the frequency may be a consequence of different contribution of electron-phonon interactions. The imaginary parts of the second order SHG susceptibility chi_{123}^{(2)}(omega), chi_{112}^{(2)}(omega), chi_{222}^{(2)}(omega), and chi_{213}^{(2)}(omega) are evaluated. We find that the 2(omega) inter-band and intra-band contributions to the real and imaginary parts of chi_{ijk}^{(2)}\l(omega) show opposite signs. The calculated second order susceptibilities are in reasonably good agreement with the experimental measurements.Comment: 16 pages, 11 figure

HOLE-DIFFUSION LENGTH AND TRANSPORT PARAMETERS OF THIN CDS FILMS FROM A SCHOTTKY BARRIER

The minority carrier diffusion length of semiconductor thin films in polycrystalline form is determined with a good precision by EBIC and LBIC techniques. The electron or laser beam used is scanned across the junction. The principle applied in these cases might be attractive for the semiconducting hand side of liquid Schottky barriers. However, these techniques cannot be easily used for such junctions. The methods based on the Gardner approach remain so far more convenient here, especially when very thin films are concerned. In this context, two independent techniques, namely, the surface photovoltage ( SPV) and the photoelectrochemical measurements served in this work

Birefringence in guest–host Ru-containing chromophore induced by acoustic field

International audienceWe have observed firstly a difference in birefringence caused by left- and right-handled circularly polarized acoustical fields for organometallic racemic tris(phenanthroline)ruthenium(II) dichloride chromophore incorporated within the polymethacrylate polymer. Within the acoustic power densities 1.2–2.2 W/cm2, this difference substantially increases up to the birefringence value of about 0.003. After the switching off of the acoustical field, the induced birefringence disappears after 14 s birefringence decay kinetics after switching off the acoustic field consists from two parts (at 8 and 14 s)