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Femtosecond laser micromachining: Applications in photonics and biology, at XIX Laser Science Conference (Tucson, AZ), Thursday, October 9, 2003:
talk_464.pdf
When femtosecond laser pulses are focused tightly into a transparent material, permanent structural or chemical changes occur. These changes can be used for micromachining bulk transparent materials. A number of applications in the fabrication of micro-optical devices and in biology and medicine will be discussed.
Memorization or understanding: Are we teaching the right thing?, at 2003 Education and Training in Optics and Photonics (Tucson, AZ), Wednesday, October 8, 2003:
talk_466.pdf
Education is more than just transfer of information, yet that is what is mostly done in large introductory courses. Few students have the ability, motivation, and discipline to synthesize all the information delivered to them. "Peer Instruction" shifts the focus in lectures from delivering information to synthesizing information and achieves remarkable improvements in student understanding.
Nano-textured Surfaces, at DEAS Industrial Outreach Workshop, Harvard University (Cambridge, MA), Friday, April 11, 2003:
talk_471.pdf
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, material and electronic properties of the original silicon wafer. These properties make the textured silicon viable for use in a wide range of commercial devices. First, near-unity absorption of light, from visible to infrared wavelengths, offer opportunities for use in optically active devices such as solar cells and detectors. Second, chemical functionalization of the... Read more about Nano-textured Surfaces
Educational Activities, at DEAS Industrial Outreach Workshop, Harvard University (Cambridge, MA), Thursday, April 10, 2003:
talk_472.pdf
The Center actively promotes interdisciplinary education and outreach through a variety of initiatives. Participants contribute to outreach to the general public through collaboration with the Boston Museum of Science, outreach to K-12 in-service teachers, research experiences for undergraduates and K-12 teachers, interdisciplinary courses for graduate students, and postdoctoral fellowships for women and minorities. The program involves faculty, postdoctoral fellows, collaborators and graduate students associated with the Center and benefits a broad constituency of society.
Black silicon: Changing structure and properties with light, at Physics colloquium, Clark University (Worcester, MA), Thursday, December 12, 2002:
talk_449.pdf
Shining intense, ultrashort laser pulses on the surface of a crystalline silicon wafer changes its structure and properties dramatically: the formerly smooth, highly reflective surface becomes covered with a forest of sharp microspikes. This microstructured surface is highly absorbing even at wavelengths to which the original wafer is transparent. This talk will describe the properties of this microstructured surface and discuss why the microspikes form and what is responsible for the change in optical properties.

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