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Magneto-optical garnets are attractive because of their high Faraday rotation and low optical loss in the near infrared. Therefore their use is generally in nonreciprocal devices, i.e., as optical isolators in optical communication. In this paper we present data concerning the deposition of Bi3Fe5O12 (BIG) thin films on (100) and (111) Gd3Ga5O12 substrates using pulsed-laser deposition. Laser-induced processes on the surface of the oxide target used for ablation were analyzed and numerous films were deposited. We found the BIG film quality to be strongly affected by oxygen pressure, laser energy density, and the Bi/Fe film ratio, whereas temperature had a minor influence. We also investigated the BIG-film deposition using a target pressed from metallic Bi and Fe powders and found information on the growth behavior of BIG. We report on details of the film deposition and film properties determined by environmental scanning electron microscopy, energy dispersive x-ray analysis, Rutherford backscattering spectroscopy, and x-ray diffraction. In addition, we determined the Faraday rotation of the films. [ABSTRACT FROM AUTHOR]

For optical communication, high quality magneto-optical active iron garnet films such as Y3Fe5O12 are important ceramic systems with extensive applications, e.g., as optical isolators [H. Dötsch et al., J. Opt. Soc. Am. B 22, 240 (2005)], optical modulators, etc. Thereby, garnets stand out due to their high Faraday rotation and low optical losses in the near infrared. Currently, it is desirable to integrate such macroscopic optical components on a single chip (Si, SiO2, etc.) to build up optical circuits as in the case of microelectronics (integrated optics) or the use for magneto-optical imaging. Up to now, Bi3Fe5O12 shows the highest Faraday rotation over 20°/μm. Unfortunately, Bi3Fe5O12 forms in a nonthermodynamical way. Thus, it can only be grown on garnet substrates which prevent it from direct deposition on substrates such as Si or SiO2. In our present work, we studied the integration of Bi3Fe5O12 on different SiO2 substrates using the pulsed laser deposition method. Therefore, we deposited an Y3Fe5O12 buffer first which was optimized in a postannealing step above 900 °C in order to form a polycrystalline garnet phase, which is needed for further Bi3Fe5O12 growth. We measured the Faraday rotation of the double layered films and intensely studied them with x-ray diffraction, Rutherford backscattering spectroscopy, environmental scanning electron microscopy, and high-resolution transmission electron microscopy. The attained Faraday rotation can be compared with epitaxial Bi3Fe5O12 films grown on Gd3Ga5O12 substrates or even overcome them due to interference effects in the double layer. So they are highly attractive for magneto-optical imaging. For the determination of the film thicknesses which is usually done by Rutherford backscattering or profilometry, we used another approach. We measured the transmission spectra of the stack which we also derived from a theoretical model that uses a transfer matrix formalism. The thickness of the multilayer can be gained by fitting the spectra. [ABSTRACT FROM AUTHOR]

Background: Modern implant systems used in the cervical region do not allow for the ingrowth of peri-implant mucosa. The aim of the present study was to use a laser to modify titanium implants used in that region in order to promote mucosa ingrowth, thereby creating a biological barrier against bacterial infection.Methods: A KrF-excimer laser (lambda=248 nm) was used (tau=30 ns, fmax=50 Hz, Emax=1.2 J). Craters were generated, under normal atmospheric conditions or in vacuum, in the polished regions of 18 Frialit 2 implants. Surface analysis was performed using a scanning electron microscope, an energy dispersive X-ray technique, and profile analysis.Results: By adjusting the parameters used, it was possible to create canals with widths of up to 100 microm and depths of 450 microm. Canal morphology was influenced by the laser energy and the surrounding atmospheric conditions. Irradiation with 3,000 pulses (650 mJ per pulse) resulted in rough surfaces under normal atmospheric conditions, whereas these parameters resulted in smooth surfaces in vacuum. The surface chemistry was also influenced by the laser parameters used.Conclusion: Laser-assisted modification of titanium surfaces permits fabrication of 3-D surface modifications. The surface chemistry can also be influenced, depending upon the parameters chosen. Further studies are necessary to evaluate whether ingrowth of mucosa into the canals can be realized. [ABSTRACT FROM AUTHOR]