HOME / PRESENTATIONS /

Contributed

Ultrafast Lattice-Bonding Dynamics in Tellurium, at CLEO/QELS 2002 (Long Beach, CA), Tuesday, May 21, 2002:
talk_429.pdf
We measure the ordinary and extraordinary dielectric function of Te with femtosecond time resolution after coherent phonons are generated with an ultrashort laser pulse. The results reveal oscillatory behavior in the bonding-antibonding split at ~ 3 THz.
Numerical aperture dependence of damage and white light generation from femtosecond laser pulses in bulk fused silica, at Photonics West 2002 (San Jose, CA), Thursday, January 24, 2002:
talk_421.pdf
The femtosecond laser has become an important tool in the micromachining of transparent materials. In particular, focusing at high numerical aperture enables structuring the bulk of materials. At low numerical aperture and comparable energy, focused femtosecond pulses result in white light or continuum generation. It has proven difficult to damage transparent materials in the bulk at low NA. We have measured the threshold energy for continuum generation and for bulk damage in fused silica for numerical apertures between 0.01 and 0.65. The threshold for continuum generation exhibits a minimum... Read more about Numerical aperture dependence of damage and white light generation from femtosecond laser pulses in bulk fused silica
Demonstrations: More Than Just Entertainment?, at 124th AAPT National Meeting (Philadelphia, PA), Wednesday, January 23, 2002:
talk_413.pdf
Does the manner of presentation determine the effectiveness of demonstrations as teaching tools? To answer this question, we improved a 1998 study by presenting seven demonstrations to sections of an introductory physics course in different ways: (1) students were shown the demonstration and the outcome explained (traditional); (2) students predicted the outcome before the demonstration; (3) students completed a worksheet in which they predicted the outcome, compared their prediction to what was observed, and resolved any inconsistency through discussion; (4) no demonstration was shown. At... Read more about Demonstrations: More Than Just Entertainment?
Manipulation of Single Cells with Sub-cellular Precision Using Femtosecond Laser Pulses, at Photonics West, Commercial and Biomedical Applications of Ultrafast Lasers IV (San Jose, CA), Wednesday, January 23, 2002:
talk_422.pdf
Femtosecond laser pulses centered at 800 nm are used 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 (BCE) cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We tightly focus femtosecond laser pulses using high numerical aperture (NA) microscope objectives to create high laser intensity in the sub-micrometer-sized focal volume. Laser energy is absorbed through non-linear... Read more about Manipulation of Single Cells with Sub-cellular Precision Using Femtosecond Laser Pulses
Gender, Educational Reform, and Instructional Assessment: Part I, at Winter Meeting, American Association of Physics Teachers (Philadelphia, PA), Tuesday, January 22, 2002:
talk_423.pdf
Why study issues of gender and physics education? It is well-known that women continue to be significantly underrepresented in careers in physics and engineering, even as representation of women improves in chemistry and the biological sciences. While many factors contribute to this state of affairs, one important area for physics educators to examine is the experiences of women in physics classes. This talk will review the current status of women in physics, the importance of studying how instruction affects the women in our classrooms, and the need for assessment instruments that do not... Read more about Gender, Educational Reform, and Instructional Assessment: Part I
Gender, Educational Reform, and Instructional Assessment: Part II, at Winter Meeting, American Association of Physics Teachers (Philadelphia, PA), Tuesday, January 22, 2002:
talk_417.pdf
Will current educational reform efforts serve to improve the learning experience of women in physics? To do so, assessment of instructional effectiveness must examine results for male and female students separately as well as for the entire class . We present an analysis of gender differences in performance in introductory physics at eight different colleges and universities; half of the courses were taught using a variety of interactive-engagement methods and half were taught with traditional lectures. We examine the effect of pedagogy and class size on the gender gap in both Force Concept... Read more about Gender, Educational Reform, and Instructional Assessment: Part II
Visible luminescence of silicon microstructures fabricated with femtosecond-laser irradiation, at International School of Atomic and Molecular Spectroscopy, Ettore Majorana Center for Scientific Culture (Erice, Sicily, Italy), Saturday, June 23, 2001:
talk_398.pdf
We report visible luminescence from SiOx formed by microstructuring silicon with femtosecond laser pulses in air. Incorporation of oxygen into the silicon lattice occurs only where the laser beam strikes the surface. Laser-structuring therefore offers the possibility to write luminescent submicron features without the use of masks. The amount of oxygen incorporated depends on the laser fluence used for microstructuring. The peak wavelength of the primary luminescence band varies between 540 and 630 nm and depends on the number of laser shots used for microstructuring. Upon annealing, the... Read more about Visible luminescence of silicon microstructures fabricated with femtosecond-laser irradiation

Pages