Poster

Academic Researchers' Joint Ventures toward Undergraduate STEM Teaching Improvement at Major Research Universities, at American Educational Research Association Annual Meeting - Poster Session (Denver, Colorado), Sunday, May 2, 2010:
Based on a qualitative study of 20 research-active science, technology, engineering and mathematics (STEM) professors’ teaching improvement efforts, this paper suggests that some academic researchers engage in highly-intensive, joint ventures to enhance their introductory pedagogy at major research universities. The study casts professors’ participation in such communal teaching activities as voluntary and as enacted despite problematic career structures that promote collaboration in research, not in teaching. Based on interviews, observations and documentary analysis, the study posits that... Read more about Academic Researchers' Joint Ventures toward Undergraduate STEM Teaching Improvement at Major Research Universities
Femtosecond laser doping of silicon for photovoltaic devices, at MIT Energy Conference, MIT (Boson, MA), Friday, April 11, 2008:
Silicon is an abundant, stable, and efficient material for use in photovoltaic devices. However, it is costly to process, and is transparent at wavelengths longer than 1100nm, a spectral region containing 25% of solar energy. The limitations of silicon have spurred significant research into complex heterostructures that capture a greater fraction of sun’s energy. Engineering silicon to extend its effective spectral range, however, might offer a simpler way to increase the efficiency and decrease the cost of silicon-based photovoltaics. We report the creation of a thin, highly absorbing layer... Read more about Femtosecond laser doping of silicon for photovoltaic devices
Femtosecond laser micromaching in the conjugated polymer MEH-PPV, at E-MRS Spring Meeting (Strasbourg, France), Thursday, May 31, 2007:
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.
Femtosecond laser-nanostructured substrates for surface enhanced Raman scattering, at Photonics West 2007 (San Jose, CA), Thursday, January 25, 2007:
We present a new substrate for efficient surface enhanced Raman scattering (SERS). Using a train of focused frequency-doubled femtosecond laser pulses from a regeneratively amplified Ti:Sapphire laser, we fabricate submicron surface structures on a silicon wafer. After irradiating the silicon wafer with 400nm, 100fs laser pulses in a cuvette of water, we observe the formation of an array of spikes, each approximately 500nm tall and 200nm wide. The wafer is scanned across the beam to form an arbitrarily-sized nanostructured area. When covered with a thin film of a noble metal, the structured... Read more about Femtosecond laser-nanostructured substrates for surface enhanced Raman scattering
Femtosecond laser doping of silicon, at Photonics West 2007 (San Jose, CA), Wednesday, January 24, 2007:
Silicon is an abundant, stable, and efficient material for use in photovoltaic devices. However, it is costly to process, and is transparent at wavelengths longer than 1100nm, a spectral region containing 25% of solar energy. The limitations of silicon have spurred significant research into complex heterostructures that capture a greater fraction of sun’s energy. Engineering silicon to extend its effective spectral range, however, might offer a simpler way to increase the efficiency and decrease the cost of silicon-based photovoltaics. We report the creation of a thin, highly absorbing layer... Read more about Femtosecond laser doping of silicon
Three-dimensional microfabrication with conjugated polymers, at 2006 MRS Fall Meetng (Boston, MA, USA), Thursday, November 30, 2006:
In this work we present new resin formulations containing active components, that can be polymerized by two-photon absorption in order to fabricate microstructures. The host resin we used consists of tris(2-hydroxyethyl)isocyanurate triacrylate, which gives hardness to the polymeric structure, ethoxylated(6) trimethyl-lolpropane triacrylate, which assists in decreasing the structure shrinkage upon polymerization, and ethyl-2,4,6-trimethylbenzoylphenylphosphinate, which acts as the polymerization photoinitiator. As guest material we used the conjugated polymer MEH-PPV, whose interesting... Read more about Three-dimensional microfabrication with conjugated polymers
Femtosecond laser micromachining in azopolymer films, at 2006 MRS Fall Meeting (Boston, MA, USA), Monday, November 27, 2006:
In this work, we investigated femtosecond laser micromachining in both poly(methyl methacrylate) (PMMA) and PMMA doped with the azoaromatic compounds Disperse Red 1 (DR1) and Disperse Red 13 (DR13). These compounds are particularly interesting due to their linear and nonlinear optical properties.
Complex microstructures fabricated via two-photon absorption polymerization, at Macro 2006 - 41st Inernational Symposium on Macromolecules (Rio de Janeiro, RG, Brazil), Sunday, July 16, 2006:
Using acrylic resin and Lucirin TPO-L as photoinitiator, we fabricated complex microstructures via the process of two photon absorption (2PA) polymerization. We measured the 2PA cross-section of Lucirin TPO-L, which is the parameter responsible for the nonlinear process, and the value found is among the ones reported in the literature for common photoinitiators. We also carried out quantum chemistry calculation in order to correlate the nonlinear optical properties of this photoinitiator to its molecular structure.
Ultrafast Frequency Dynamics of Coherent Phonons in Te Under High Density Photoexcitation, at Photonics West 2006 (San Jose, CA), Wednesday, January 25, 2006:
We report on the ultrafast dynamics of large amplitude A1 coherent optical phonons in Te after excitation with femtosecond laser pulses. Using time-resolved pump-probe dielectric tensor measurements on a single crystal Te sample we can monitor the excitation of the A1 phonon mode due to photoexcited carrier density redistribution. By performing a short-term Fourier transform of the observed dielectric tensor oscillations we can track the evolution of their local frequency and determine the time-resolved frequency response of the photoexcited A1 phonon mode.

The purpose of the experiment...

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