BACKGROUND With the aim of developing methods that could increase the fracture resistance of structurally compromised endodontically treated teeth, this study was conducted to compare the effect of three esthetic post systems on the fracture resistance and failure modes of structurally compromised and normal roots. MATERIALS AND METHODS Forty five extracted and endodontically treated maxillar...

A novel method for fabricating microlenses on tapered single-mode fibers is shown to be able to control the lens spot size. The fiber cladding is first symmetrically tapered by etching it with an evaporating ammonium bifluoride solution. A hemispheric lens is then melted on the taper tip with a CO(2) laser. The lens can reduce the fiber mode radius to 40% of its original value. A theoretical ca...

A simple refractive index sensor based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a single symmetrically abrupt taper region in a short piece of single-mode fiber that is terminated by approximately 500 nm thick gold coating. The sensitivity of the new sensor is similar to that of a long-period-grating-type sensor, and its ease o...

Surface plasmon resonance based tapered fiber optic refractive index sensor incorporating an additional high index dielectric layer between metal and sensing medium using wavelength interrogation method is analyzed. The simulation is carried out for gold and silver metals. The simulation predicts, for a given taper ratio, the increase in the sensitivity of the sensor with increase in the thickn...

We experimentally find a practical stimulated Brillouin scattering (SBS) threshold for broadband high-performance fiber optical parametric devices relying on dispersion-stable GeO2-doped silica highly nonlinear fibers. demonstrate that SBS limits the phase shift in such fibers to ~0.3 rad per pump unless is mitigated some way. consequently derive corresponding signal gain and conversion efficie...