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Femtosecond-laser microstructuring of silicon for photovoltaic devices, at Photonics West 2006 (San Jose, CA), Tuesday, January 24, 2006:
talk_1174.pdf
Photovoltaics research has recently focused on photovoltaic materials made by cheaper processes with minimal waste such as thin-films grown by chemical vapor deposition. Because silicon is the most common semiconductor material and the second most abundant element in the earth, silicon-based thin films are an excellent choice for photovoltaics. The drawback to crystalline silicon thin films is low absorption due to silicon’s indirect band gap. Thicker films increase processing costs and sacrifice efficiency due to defects inherent in the thin-films.

We report the creation of a thin,...

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Sub-cellular nanosurgery in live cells using ultrashort laser pulses, at Photonics West 2006 (San Jose, CA), Sunday, January 22, 2006:
talk_1176.pdf
We use femtosecond laser pulses to selectively disrupt the cytoskeleton of a living cell and probe its mechanical properties. The nanosurgery setup is based on a home-built two-photon microscope. To image, we use a 80-MHz, 100-pJ/pulse laser beam, which is scanned across the sample; to cut, we introduce a second, 250-kHz, 1 to 5-nJ/pulse, laser beam and locally ablate sub-cellular structures. Simultaneous cutting and imaging allows us to study immediate cellular response with several hundred-nanometer spatial and less than 500-ms time resolution.

We severed single actin bundles inside...

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Single neuron dissection in C. elegans by femtosecond laser pulses, at Photonics West 2006 (San Jose, CA), Saturday, January 21, 2006:
talk_1179.pdf
Using tightly-focused, 2-5 nJ femtosecond laser pulses we disrupt cellular material in the nematode worm C. elegans. Due to the nonlinear absorption of laser light, the dissection has submicrometer resolution, yielding surgery within the bulk of the worm without incision. The low energy of the pulses minimizes collateral damage. This technique permits subcellular surgery on live animals and opens a wide range of neurobiological questions to study in vivo.

We severed individual dendrites of a thermosensory neuron without damaging nearby neurons. Quantification of the resulting behavioral...

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Reversible birefringence in microstructures, at CLEO 2006 (Longbeach, CA, USA), Thursday, January 5, 2006:
talk_1276.pdf
We use two-photon absorption polymerization to fabricate optically active microstructures that exhibit optically-induced birefringence and dichroism. Our results open the door to new applications in data storage, waveguides and optical circuitry
Technology for Peer Instruction, at AAPT Summer Meeting (Salt Lake City, Utah), Tuesday, August 9, 2005:
talk_1148.pdf
The Interactive Learning Toolkit (ILT) is a tool to implement innovative teaching ideas such as Peer Instruction and Just in Time Teaching, and to monitor students’ learning. It incorporates a large Concept Test (CT) database and provides the opportunity to easily integrate CTs into lectures. This talk will discuss the integration of the content management of the ILT with the Interactive Classroom features of BQ, a software developed at Erskine College. Student responses using IR clickers, wireless laptops, PDAs and cell phones are combined to give the instructor immediate feedback on student... Read more about Technology for Peer Instruction
Femtosecond laser dissection of neurons in C. elegans, at NATO ASI Course on New developments in optics and related fields: modern techniques, materials, and applications, Centro Ettore Majorana (Erice, Italy), Tuesday, June 14, 2005:
talk_1169.pdf
Tightly-focused femtosecond laser pulses of a few nanojoules sever individual dendrites in the nematode worm C. elegans. Quantification of the resulting behavioral deficits identifies the contribution of the dissected structures. Due to nonlinear absorption of laser light, the dissection has submicrometer resolution with no collateral damage, permitting subcellular surgery on live animals. Future work include an examination of the molecular basis of neurodegeneration that has application to diseases such as Parkinsons and Alzheimers.
Sub-cellular femtosecond laser ablation, at 2005 SPIE Photonics West Conference (San Jose, CA), Wednesday, January 26, 2005:
talk_1082.pdf
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

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