Presentations

    Femtosecond Micromachining of Transparent Materials, at International School of Atomic and Molecular Spectroscopy (Erice, Sicily), Friday, May 23, 2003:
    We present an overview of femtosecond microstructuring of transparent materials. Bulk structuring of transparent materials can be achieved by focusing high-intensity femtosecond pulses. The morphology of the structures depends on the incident energy per pulse and on the focusing conditions. At high focusing conditions the damage threshold in silicate glasses is just a few nanojoules. This energy range is available from an oscillator. We have demonstrated laser writing of embedded waveguides in silicate glasses with a femtosecond oscillator. Laser machining at high laser repetition rate... Read more about Femtosecond Micromachining of Transparent Materials
    Femtosecond laser micromachining, at Photonics West 2006 (San Jose, CA), Tuesday, January 24, 2006:
    When femtosecond laser pulses are focused tightly into a transparent material, the intensity in the focal volume can become high enough to cause nonlinear absorption of laser energy. The absorption, in turn, can lead to permanent structural or chemical changes. Such changes can be used for micromachining bulk transparent materials. Applications include data storage and the writing of waveguides and waveguide splitters in bulk glass, fabrication of micromechanical devices in polymers, and subcellular photodisruption inside single cells.
    Supercontinuum and second harmonic generation in amorphous silica nanowires, at Glass & Optical Materials Division Fall 2004 Meeting (Cocoa Beach, FL), Wednesday, November 10, 2004:
    We developed a technique for drawing long, free-standing silica nanowires with diameters down to 50 nm and lengths up to 40 mm. The wire core is amorphous and of very uniform diameter. The wire surface has atomic level smoothness. The wire can guide a single mode of visible or near-infrared light. Because the diameter of the fiber is smaller than the wavelength, however, a large portion of the guided light is in the form of an evanescent field surrounding the nanowire. When amplified femtosecond laser pulses are coupled into these wires, surprising nonlinear optical effects are observed: in... Read more about Supercontinuum and second harmonic generation in amorphous silica nanowires
    Supercontinuum in silica nanowires, at Photonics West 2006 (San Jose, CA), Thursday, January 26, 2006:
    Fibers are gaining widespread acceptance for generating ultra-broad spectra. The most common approach involves a photonic crystal fiber with carefully designed core size and dispersion characteristics. Although this system provides confinement of light to micrometer (and sometimes sub-micrometer) dimensions, this confinement is achieved at the expense of a complex core structure. An alternative to microstructured fibers is the use of silica fibers with sub-wavelength diameters whose waveguiding properties were initially demonstrated by our group. Silica nanowires are a model system because... Read more about Supercontinuum in silica nanowires
    Morphology and optical properties of femtosecond irradiated glass with variable pulse repetition rates, at Glass & Optical Materials Division Fall 2004 Meeting (Cocoa Beach, FL), Tuesday, November 9, 2004:
    We investigated the morphology of femtosecond irradiated borosilicate glass with respected to two variables: the number of shots and the laser repetition rate. For the laser repetition rate we have covered the range from 250 kHz to 25 MHz. We identify two distinct regimes of femtosecond processing in the kHz to MHz range. As the time interval between pulses is reduced, we observe a transition from a repetitive modification process (identical to what is frequently called multiple shot damage) to a cumulative thermal mechanism. In the repetitive regime, each pulse acts independently and the... Read more about Morphology and optical properties of femtosecond irradiated glass with variable pulse repetition rates
    Nonlinear optics at the nanosale, at Ultrafast Optics 2007 (Santa Fe, NM), Wednesday, September 5, 2007:
    Silica nanowires are a model system for the propagation of light at the nanoscale. Because of the tight confinement of light provided by these nanowires, nonlinear effects can be observed with pulse energies in the picojoule range, opening the door to a new class of nanophotonic devices. In addition, silica nanowires permit convenient coupling between macroscale and nanoscale. We will show how silica nanowires can be used to study waveguiding, mode propagation, and nonlinear effects in single ZnO nanowires.