BaTiO3 and BaTiO3:Ce thin films with good surface morphology and tetragonal perovskite structure were fabricated on quartz substrates by pulsed-laser deposition technique at a deposition temperature of 750 °C The fundamental optical constants (the band gaps, linear refractive indices and absorption coefficients) of the films were obtained through optical transmittance measurements The nonlinear optical properties of the films were investigated using Z-scan method The films display large nonlinear absorption effects The two-photon absorption coefficients of the BaTiO3 and BaTiO3:Ce films were determined to be 517 and 593 cm/GW, respectively All the results show that undoped and cerium-doped BaTiO3 ferroelectric thin films have potential applications in absorbing-type optical devices

Nonlinear optical absorption in undoped and cerium-doped BaTiO3 thin films using Z-scan technique

Microsphere resonator circuits have emerged as a technology allowing integration of cavities in all three spatial dimensions (3D) in chip-scale structures. This presentation is devoted to fabrication, optical properties and applications of mesoscale structures formed by microspheres. The “mesophotonics” properties of such structures stem from two properties of individual dielectric microspheres with dimensions comparable to the wavelength of light: (i) high quality factors of whispering gallery modes (WGMs) and (ii) subwavelength dimensions of the focused spots termed “photonic nanojets”. Traditionally, the resonant optical transport properties of such structures have been described by a tight binding approximation for photonic atoms. Recently we showed that the WGM-based transport in 2D and 3D systems with disorder can be understood on the basis of analogy with a percolation theory. Along with these resonant coupling effects very interesting properties of periodical focusing of light were observed in long chains of spheres. These properties were explained due to formation of nanojet-induced modes with small propagation losses. At the device level, these studies stimulate developing designs where coupled cavities are applied to developing narrow spectral filters, delay lines, arrayed-resonator light emitting devices, tight focusing micro-probes, sensors, and compact spectrometers.

Fundamentals and applications of microsphere resonator circuits

Luminescence and spectroscopic investigations on Gd3+ doped ZnO nanophosphor

Effects of isothermal annealing on the oxidation behavior, mechanical and thermal properties of AlN ceramics

(2+1)-dimensional optical spatial solitons have become a major field of research in nonlinear physics throughout the last decade due to their potential in adaptive optical communication technologies. With the help of photorefractive crystals that supply the required type of nonlinearity for soliton generation, we are able to demonstrate experimentally the formation, the dynamic properties, and especially the interaction of solitary waves, which were so far only known from general soliton theory. Among the complex interaction scenarios of scalar solitons, we reveal a distinct behavior denoted as anomalous interaction, which is unique in soliton-supporting systems. Further on, we realize highly parallel, light-induced waveguide configurations based on photorefractive screening solitons that give rise to technical applications towards waveguide couplers and dividers as well as all-optical information processing devices where light is controlled by light itself. Finally, we demonstrate the generation, stability and propagation dynamics of multi-component or vector solitons, multipole transverse optical structures bearing a complex geometry. In analogy to the particle-light dualism of scalar solitons, various types of vector solitons can - in a broader sense - be interpreted as molecules of light.

https://www.uni-muenster.de/imperia/md/content/physik_ap/denz/publikationen/2002/2002_4.pdf

Spatial optical (2+1)‐dimensional scalar‐ and vector‐solitons in saturable nonlinear media

Z-scan experiments with cubic photorefractive crystal Bi12TiO20

Optical percolation in ceramics assisted by porous clusters

Transient self-bending of laser beams in photorefractive crystals with drift nonlinearity

Using electron microscopy and X-ray microanalysis, the formation of tracks by laser processing of AlN:Y 2 O 3 ceramic surfaces was investigated. The main process of channel formation is the decomposition of aluminum nitride (AlN). Due to aluminothermic reduction of Y 2 O 3 , the metallization of channel surfaces occurs. The main products of ablation are Al 2 O 3 , AlN, and AlON.

P.A. Márquez Aguilar

Papers

Z-scan experiments with cubic photorefractive crystal Bi12TiO20

Optical percolation in ceramics assisted by porous clusters

Transient self-bending of laser beams in photorefractive crystals with drift nonlinearity

Features of formation of channels during laser treatment of AlN ceramics

Improvement of photovoltaic performance of inverted hybrid solar cells by adding single-wall carbon nanotubes in poly(3-hexylthiophene)