2005

Memorization or understanding: Are we teaching the right thing?, at 229th American Chemical Society National Meeting (San Diego, CA), Sunday, March 13, 2005:
Education is more than just transfer of information, yet that is what is mostly done in large introductory courses -- instructors present material (even though this material might be readily available in printed form) and for students the main purpose of lectures is to take down as many notes as they can. Few students have the ability, motivation, and discipline to synthesize all the information delivered to them. Yet synthesis is perhaps the most important -- and most elusive -- aspect of education. I will show how shifting the focus in lectures from delivering information to synthesizing... Read more about Memorization or understanding: Are we teaching the right thing?
Nanowiring light, at Optical Fiber Communication Conference 2005 (Anaheim, CA), Thursday, March 10, 2005:
Recent advances in the fabrication and manipulation of sub-wavelength optical fibers provide new methods for building chemical and biological sensors, generating supercontinuum light by nonlinear pulse propagation, and constructing microphotonic components and devices.
Wrapping Light around a Hair, at Applied Physics-OSA Optics Seminar, California Institute of Technology (Pasadena,), Thursday, March 10, 2005:
Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was ‘no’. We developed a technique for drawing long, free-standing silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a high uniformity of diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it... Read more about Wrapping Light around a Hair
Femtosecond laser micromachining, at French-Israeli Symposium on Non-linear and Quantum Optics (Ein Bokek, Israel), Wednesday, February 23, 2005:
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.
Optical waveguide fabrication for integrated photonic devices, at Optical and Electronic Device Technology for Access Network: Nanophotonics and functional device technology (San Jose, CA), Thursday, January 27, 2005:
The dynamic nature of future optical networks requires high levels of integration, fast response times, and adaptability of the optical components. Laser micromachining circumvents the limitations of planar integration, making three-dimensional integration possible and allowing dense packaging of optical devices with no alignment requirements. Femtosecond micromachining provides the analog of circuit printing by wiring light between various photonic devices as well as printing the actual photonic device into a single or various substrates. Oscillator-only machining has several advantages over... Read more about Optical waveguide fabrication for integrated photonic devices
Sub-cellular femtosecond laser ablation, at 2005 SPIE Photonics West Conference (San Jose, CA), Wednesday, January 26, 2005:
We study the selective ablation by femtosecond laser pulses of sub-cellular structures in bovine endothelial cells, with selectively stained microtubules, actin fibers, and nuclei. The cells are placed in a custom-built inverted fluorescence microscope with a 1.4 NA oil-immersion objective. The laser used for ablation is centered at 800 nm delivering 100-fs laser pulses at a repetition rate of 1 kHz and the typical energy delivered at the sample is 1–5nJ. To determine the structural change and the size of the laser-affected area, we use transmission electron microscopy (TEM), in addition to... Read more about Sub-cellular femtosecond laser ablation
Femtosecond Laser Micromachining: Applications in Technology and Biology, at 2005 SPIE Photonics West Conference, Symposium OE04: Ultrafast Phenomena in Semiconductors and Nanostructure Materials IX (San Jose, CA), Wednesday, January 26, 2005:
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. In this talk we will review recent results obtained in... Read more about Femtosecond Laser Micromachining: Applications in Technology and Biology
Femtosecond-laser micromachining of silicon for novel optoelectronic devices, at 2005 SPIE Photonics West Conference (San Jose, CA), Tuesday, January 25, 2005:
Silicon is the most commonly used semiconductor in micro- and optoelectronics. However, silicon is not the best material for all applications: as an indirect band-gap material, it is a poor light emitter; silicon cannot be used to detect many important communications wavelengths; and silicon solar cells fail to convert nearly a third of the suns’ spectrum into electricity. The low cost and large manufacturing infrastructure drives research to alter the properties of silicon rather than rely on more exotic semiconductor materials. We present a novel technique that uses the intense conditions... Read more about Femtosecond-laser micromachining of silicon for novel optoelectronic devices
Nanosurgery in live cells using ultrashort laser pulses, at 2005 SPIE Photonics West Conference (San Jose, CA), Tuesday, January 25, 2005:
We selectively disrupted the cytoskeletal network of a live bovine capillary endothelial cell using ultrashort laser pulses. We image the microtubules in the cytoskeleton of the cultured cells using green fluorescent protein. The cells are placed on a custom-built inverted fluorescence microscope setup, using a 1.4 NA oil-immersion objective to both image the cell and focus the laser radiation into the cell samples. The laser delivers 100-fs laser pulses centered at 800 nm at a repetition rate of 1 kHz; the typical energy delivered at the sample is 1–5nJ. The fluorescent image of the cell is... Read more about Nanosurgery in live cells using ultrashort laser pulses
Optical waveguide wiring using femtosecond laser pulses between multiple pieces of glass for optical sensor applications, at 2005 SPIE Photonics West Conference, Program on Laser Micro-/Nanoengineering and applications, Commercial and Biomedical Applications of Ultrafast Lasers VI (San Jose, CA), Tuesday, January 25, 2005:
We demonstrate optical waveguide wiring between multiple pieces of glass using high-repetition rate femtosecond laser pulses focused with a 1.4 NA oil-immersion microscope objective. In conventional waveguide wiring techniques, connecting optical waveguides in different pieces of glass requires special attention because of the very small core size of the waveguides. Connecting waveguides therefore necessitates highly accurate positioning stages and is a time consuming process. We demonstrate that it is possible to write optical waveguides across the gap between two pieces of glass with a... Read more about Optical waveguide wiring using femtosecond laser pulses between multiple pieces of glass for optical sensor applications

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