In this study we report the physical properties and spontaneous Raman scattering spectra of nine oxide tellurite and fluorotellurite glasses from three glass systems—sodium–zinc–tellurite (TZN), tungsten–tellurite, and fluorotellurite. Raman gain and surface damage threshold at 1064 nm are also shown for a selection of these glasses, which all exhibited high gain and damage resistance. Raman gain spectra were directly measured and accurately calculated for selected TZN and fluorotellurite glasses after Fresnel, internal solid angle, and Bose–Einstein corrections. The calculated gain showed good fits to the Raman gain measurements made using a calibrated nonlinear optics apparatus. Infrared and UV‐Vis absorption spectra, characteristic temperatures obtained by differential thermal analysis, densities acquired by the Archimedes principle and refractive indices measured by spectroscopic ellipsometry are also given. The ternary systems TeO2–WO3–Bi2O3 and TeO2–Na2O–ZnF2 and the quaternary system TeO2–Na2O–ZnO–PbO show promise as Raman amplifiers as they are relatively easy to draw into optical fiber and to these authors' knowledge, this is the first time Raman gain has been presented on halide containing tellurite glasses. The oxyfluoride system studied here, TeO2–Na2O–ZnF2, exhibited a dependence on the peak Raman intensity with ZnF2 addition. Calculations of preform geometry for mono‐ and multimode guidance and stresses in similar and dissimilar (core suction) core–clad pairs are shown. Dispersion in the mid‐infrared and initial fiber drawing studies are also reported with fibers showing reasonable unclad losses.

Buried waveguides in glass are manufactured by irradiation with femtosecond laser double pulses. The refractive index change Deltan is determined by measuring the numerical aperture NA of the waveguides and by through light microscopy. The value of Deltan shows a significant dependency on the time delay Deltat of the fs-laser double pulses. A Deltan of up to 2x10(-3) in fused silica is reached at a Deltat between 400 and 800 ps. Based on the results of the double pulse experiments the initial effects of the refractive index change are discussed, taking into account thermal effects and the formation of self trapped excitons (STE) and transient color centers and their interaction with the next laser pulse.

No abstract

Using femtosecond filaments for the ablation of GaAs in air, we have observed that the diameter and volume of the resulting ablation craters remained almost constant with propagation distance. This constant mass removal along the propagation of a filament in both focused and non-focused configurations is valuable for applications such as material processing and stand-off laser-ablation based spectroscopy.

A simple approach to producing a 1×N beam splitter is demonstrated by fabricating a volumetric multiplex phase Fresnel zone plate in bulk transparent material. This comprised four layers of zone plates created in borosilicate glass by femtosecond laser direct-writing, each shifted laterally relative to the illumination axis, creating four separate beamlets. Since the power transmitted in each beamlet is proportional to the diffraction efficiency of the corresponding zone plate, the power ratios can be customized by adjusting the fabrication parameters of each layer. This approach demonstrates the potential of femtosecond laser direct-writing for the fabrication of complex optical elements in transparent media as components of integrated monolithic photonic devices.