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2007

Femtosecond laser micromaching in the conjugated polymer MEH-PPV, at E-MRS Spring Meeting (Strasbourg, France), Thursday, May 31, 2007:
talk_1332.pdf
Femtosecond-laser micromachining of poly[2-methoxy-5-(2’-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) films is investigated using 130-fs pulses at 800-nm from a laser oscillator operating at 76-MHz repetition rate. We investigate the effect of pulse energy and translation speed on the depth and morphology of the micromachined regions. We quantified the MEH-PPV photobleaching induced by the fs-laser, and the conditions in which the emission of MEH-PPV is preserved after the micromaching.
Confessions of a converted lecturer, at International Conference, Fundação Serralves (Oporto, Portugal), Tuesday, May 15, 2007:
talk_1327.pdf
I thought I was a good teacher until I discovered my students were just memorizing information rather than learning to understand the material. Who was to blame? The students? The material? I will explain how I came to the agonizing conclusion that the culprit was neither of these. It was my teaching that caused students to fail! I will show how I have adjusted my approach to teaching and how it has improved my students' performance significantly
Subcellular surgery and nanosurgery, at CLEO 2007 (Baltimore, MD), Thursday, May 10, 2007:
talk_1214.pdf
We use femtosecond laser pulses to probe the mechanical propertiesof the actin network in live cells and to probe cell regeneration and the neurological basis of behavior in C. elegans.
Education, at Parent Leadership Weekend, Harvard University (Cambridge, MA), Friday, May 4, 2007
No abstract available.
Femtosecond laser micromachining, at MIT Center for Integrated Photonic Systems Annual Meeting, MIT (Cambridge, MA, USA), Thursday, May 3, 2007:
talk_1318.pdf
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.
Femtosecond laser ablation of silicon: nanoparticles, doping and photovoltaics, at Harvard University (Thesis Defense) (Cambridge, MA), Friday, April 27, 2007:
talk_1328.pdf

In this thesis, we investigate the irradiation of silicon in a background gas of near atmospheric pressure with intense femtosecond laser pulses at energy densities exceeding the threshold for ablation (the macroscopic removal of material). We study the resulting structure and properties of the material ejected in the ablation plume as well as the laser irradiated surface itself.

The material collected from the ablation plume is a mixture of single crystal silicon nanoparticles and a highly porous network of amorphous silicon. The crystalline nanoparticles form by nucleation...

Read more about Femtosecond laser ablation of silicon: nanoparticles, doping and photovoltaics
Subcellular surgery and nanosurgery, at Physics Colloquium, University of Massachusetts Lowell (Lowell, MA), Wednesday, April 25, 2007:
talk_1287.pdf
We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery
Confessions of a converted lecturer, at 2007 Teaching and Learning Conference, University of Minnesota (Minneapolis, MN), Monday, April 23, 2007:
talk_1221.pdf
I thought I was a good teacher until I discovered my students were just memorizing information rather than learning to understand the material. Who was to blame? The students? The material? I will explain how I came to the agonizing conclusion that the culprit was neither of these. It was my teaching that caused students to fail! I will show how I have adjusted my approach to teaching and how it has improved my students' performance significantly.

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