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We report on femtosecond laser writing of channel waveguides in Nd 3+ ion doped YAG ceramics by multiple inscriptions of damage filaments. Waveguiding between filaments was found to resist annealing temperatures as high as 1500°C. Microluminescence imaging experiments have been carried out to elucidate the potential application of the obtained waveguides as integrated laser sources as well as to elucidate the waveguiding mechanisms. © 2010 Optical Society of America OCIS codes: 230.7380, 180.2520, 160.3380. Neodymium-doped transparent YAG ceramics (hereafter Nd:cYAG) is nowadays one of the most promising laser materials with outstanding properties [1][2][3]. The future incorporation of Nd:cYAG in compact devices requires the fabrication of channel waveguides in which the 2D light confinement would lead to a much higher optical intensities. Among the different methods already used for the fabrication of channel waveguides in the Nd:cYAG system [4], direct laser writing with femtosecond pulses is of special relevance because of its reduced processing times, its simplicity, and its true 3D versatility [5]. In the case of a Nd:cYAG system, waveguides based on the so-called double-line approach have shown excellent optical and superior laser properties [6,7]. The main drawback of these waveguides is the instability of the strain-field-induced refractive index increment, i.e., of the waveguide, against thermally induced lattice relaxation [6]. This is a negative aspect in laser waveguides, where relevant pump induced thermal loadings are expected to occur [8].In this Letter we report on the fabrication of thermally resistant Nd:cYAG waveguides by an approach consisting of the consecutive inscription of two orthogonal pairs of femtosecond filaments. The ability of the obtained structure for light confinement and its thermal stability has been investigated. The potential application of the obtained waveguides as laser sources has been explored by luminescence imaging experiments.The Nd:cYAG sample used in this work was provided by Baikowskii Ltd. (Japan) and was a 1 ϫ 1 ϫ 1 cm 3 prism with a nominal Nd 3+ concentration of 2 at. %. Damage filaments were inscribed by using an amplified Ti:sapphire laser system providing 120 fs pulses linearly polarized at 796 nm and 1 kHz of repetition rate. The laser beam was focused 250 m below the surface with a 10ϫ microscope objective ͑NA= 0.3͒. The on-target pulse energy was set to 3 J, leading to ϳ40-m-long filaments. In a first step, two filaments were written separated 30 m by translating the sample in the direction perpendicular to the laser polarization and the pulse propagation, with a speed of 50 m / s. Then the sample was turned 90°and a second pair of filaments, overlapping to the first one was inscribed. The end-face of the obtained quadruple-line structure is shown in Fig. 1(a). The ability of the obtained structure as an optical waveguide was investigated by both endcoupling experiments using a He-Ne laser [ Fig. 1(b)] as well as by transmission scanning near-field m...

PURPOSE. Successful intraocular lens procedures, that is, implantation of accommodating intraocular lenses (A-IOL), require firm engagement of the IOL haptics to the capsular bag. We evaluated the use of photochemical bonding to engage IOL materials to the capsular bag.METHODS. Freshly enucleated eyes of New Zealand rabbits were used in two types of photobonding experiments using Rose Bengal (RB) photoinitiation and green light (532-nm) irradiation. First, RB-stained capsular bag strips were photobonded ex vivo to IOL polymer [poly(2-hydroxyethyl methacrylate) pHEMA] strips in an atmosphere of air and of nitrogen. Second, IOLs were implanted intracapsularly and photobonded intraocularly. Irradiation times were between 30 and 180 seconds, and laser irradiance was between 0.25 and 0.65 W/cm 2 . The strength of the bonding was tested using a custom-developed uniaxial extensiometry system and the breakage load (the load that caused breakage per bonded area) was calculated.RESULTS. The breakage load of ex vivo capsule-pHEMA bonds increased exponentially with irradiation time, using 0.45 W/cm 2 . In air, the average breakage load across all conditions was 1 g/mm 2 and 1.6 times lower than that in a nitrogen atmosphere. Intraocularly, RB-stained IOLs were strongly photobonded to the capsule bag with breakage loads > 0.8 g/mm 2 .CONCLUSIONS. Breakage of the photobonded linkage between IOL material and capsular bag required loads substantially greater than the maximum force of ciliary muscle, suggesting that this technology may introduce a new paradigm for engagement of A-IOLs. The bonding produced in air was stronger than that in nitrogen atmosphere, suggesting that oxygen is involved in the chemical mechanism for photobonding.

A study of Ba(2)NaNb(5)O(15) and LiNbO(3) crystals with periodic ferroelectric domain structures using the scanning near field optical microscopy technique is reported. Optical contrast is observed in the regions of ferroelectric domain boundaries and it is analysed using beam propagation method modelling. This reveals that the optical contrast, a consequence of changes in the refractive index, is not due to variation of the waveguide-coupling efficiency, and supports the hypothesis that it is associated with the domain array, which is related to the size of the domain.

Multilayers of MgF2 and Sb2S3 have been obtained by physical vapour deposition on glass substrates. Changes in the optical and structural properties have been studied as a function of annealing temperature and the number of layers. A drastic variation in optical transmission, microstrain and grain size is observed at a temperature near 225 °C. A comparison of the material properties of multilayers and a monolayer is carried out.