Invited

Ultrafast laser-processing of materials, at APS March Meeting (Indianapolis, IN), Monday, March 18, 2002:
The dielectric function response of Te to ultrashort pulse laser excitation reveals oscillatory behavior in the bonding-antibonding split due to the presence of coherent phonons, suggesting a THz-driven semiconductor-semimetal transition.
Ultrafast laser microtexturing of silicon for optoelectronic devices, at Photonics West: Commercial and Biomedical Applications of Ultrafast Lasers (San Jose, CA), Thursday, January 24, 2002:
Arrays of sharp, conical microstructures are obtained by texturing the surface of a silicon wafer using femtosecond laser-assisted chemical etching. The one step, maskless texturing process drastically changes the optical and electronic properties of the original silicon wafer. These properties make the textured silicon viable for use in a wide range of commercial devices. Near-unity absorption of light, from visible to infrared wavelengths, offer opportunities for use in optically active devices such as solar cells and detectors. Significant enhancement of below-band-gap photocurrent... Read more about Ultrafast laser microtexturing of silicon for optoelectronic devices
Classroom Demonstrations: More Than Just Entertainment?, at Physics Colloquium, Worcestert Polytechnic Institute (Worcester, MA), Monday, November 19, 2001
Classroom demonstrations in science courses are intended to serve two important purposes: to increase students’ interest in the material being covered and to improve students’ understanding of the underlying scientific concepts. Student end-of-semester evaluations typically praise demonstrations as one of the most interesting parts of a course, suggesting that demonstrations accomplish the first objective. What about the second? Do demonstrations effectively help students learn the underlying concepts? We examined whether the manner of presentation of demonstrations affects their... Read more about Classroom Demonstrations: More Than Just Entertainment?
Black silicon: Microstructuring silicon with femtosecond lasers, at Physics Colloquium, University of Massachusetts-Lowell (Lowell, MA), Wednesday, November 14, 2001:
Our research group has produced a novel form of microstructured silicon ("black silicon") with many surprising properties: near unity absorption, even below the band gap; production of photoelectrons in the visible and infrared; visible luminescence; and a strong field emission current. This talk will describe these properties and what is understood so far about their structural and chemical origin.
Classroom Demonstrations: More Than Just Entertainment?, at Physics colloquium, Calvin College (Grand Rapids, MI), Thursday, September 27, 2001:
Classroom demonstrations in science courses are intended to serve two important purposes: to increase students’ interest in the material being covered and to improve students’ understanding of the underlying scientific concepts. Student end-of-semester evaluations typically praise demonstrations as one of the most interesting parts of a course, suggesting that demonstrations accomplish the first objective. What about the second? Do demonstrations effectively help students learn the underlying concepts? We examined whether the manner of presentation of demonstrations affects their... Read more about Classroom Demonstrations: More Than Just Entertainment?
Laser induced microexplosions and applications in laser micromachining, at Annual Meeting of the Stanford Photonics Research Center, Standord University (Palo Alto, CA), Saturday, September 15, 2001:
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 Laser induced microexplosions and applications in laser micromachining

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