2008

Nonlinear optics at the nanoscale, at the Boston LEOS Chapter, MIT Lincoln Laboratories (Lincoln, MA), Thursday, December 11, 2008:
We explore nonlinear optical phenomena at the nanoscale by launching femtosecond laser pulses into long silica nanowires. Using evanescent coupling between wires we demonstrate a number of nanophotonic devices. At high intensity the nanowires produce a strong supercontinuum over short interaction lengths (less than 20 mm) and at a very low energy threshold (about 1 nJ), making them ideal sources of coherent white-light for nanophotonic applications. The spectral broadening reveals an optimal fiber diameter to enhance nonlinear effects with minimal dispersion. We also present a device that... Read more about Nonlinear optics at the nanoscale
Comprensión o memorización: Estamos haciendo lo correcto?, at Primer Congreso Internacional sobre Enseñanza en Física, Escuela Superior Politécnica del Litoral (Guayaquil, Ecuador), Thursday, November 20, 2008:
Education is more than just transfer of information, yet that is what is mostly done in large introductory courses -- instructors present material (even though this material might be readily available in printed form) and for students the main purpose of lectures is to take down as many notes as they can. Few students have the ability, motivation, and discipline to synthesize all the information delivered to them. Yet synthesis is perhaps the most important -- and most elusive -- aspect of education. I will show how shifting the focus in lectures from delivering information to synthesizing... Read more about Comprensión o memorización: Estamos haciendo lo correcto?
Active learning in your classroom, at Workshop for HSPH Faculty, Docs, and Post Docs, Harvard School of Public Health (Boston, MA), Wednesday, November 12, 2008:
The basic goals of Peer Instruction are to encourage and make use of student interaction during lectures, while focusing students' attention on underlying concepts and techniques. The method has been assessed in many studies using standardized, diagnostic tests and shown to be considerably more effective than the conventional lecture approach to teaching. Peer Instruction is now used in a wide range of science and math courses at the college and secondary level. In this workshop, participants will learn about Peer Instruction, serve as the “class” in which Peer Instruction is demonstrated,... Read more about Active learning in your classroom
Peer Instruction Workshop, at New Physics and Astronomy Faculty Workshop, American Center for Physics (College Park, MD), Thursday, November 6, 2008:
The basic goals of Peer Instruction are to encourage and make use of student interaction during lectures, while focusing students' attention on underlying concepts and techniques. The method has been assessed in many studies using standardized, diagnostic tests and shown to be considerably more effective than the conventional lecture approach to teaching. Peer Instruction is now used in a wide range of science and math courses at the college and secondary level. In this workshop, participants will learn about Peer Instruction, serve as the “class” in which Peer Instruction is demonstrated,... Read more about Peer Instruction Workshop
Introduction to Peer Instruction, at New Physics and Astronomy Faculty Workshop, American Center for Physics (College Park, MD), Thursday, November 6, 2008:
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 Physics Colloquium, University of Massachusetts Boston (Boston, MA), Wednesday, November 5, 2008:
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
Femtosecond laser interactions with materials: from micromachining to microsurgery, at Materials Science and Engineering Colloquium, Stanford University (Palo Alto, CA), Friday, October 31, 2008:
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, and fabrication of micromechanical devices in polymers.

We have used this technique to manipulate sub-cellular structures inside live and fixed cells. Using...

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Confessions of a converted lecturer, at Award Winning Teachers on Teaching Lecture, Stanford University (Palo Alto, CA), Thursday, October 30, 2008:
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
The make-believe world of real-world physics, at Teaching and Learning Center Public Lecture, Stanford University (Palo Alto, CA), Thursday, October 30, 2008:
That physics describes the real world is a given for physicists. In spite of tireless efforts by instructors to connect physics to the real world, students walk away from physics courses believing physicists live in a world of their own. Are students clueless about the real world? Or are we perhaps deluding ourselves and misleading our students about the real world?
Extending silicon's reach: nonequlibrium doping using ultrafast lasers, at Physics Colloquium, University of Massachusetts, Lowell (Lowell, MA), Wednesday, October 22, 2008:
Silicon is the world's widely used semiconductor. As the building block of a photovoltaic cell, silicon offers the best combination of stability, efficiency, and manufacturability. However, as an indirect absorber of light, thick layers of highly-pure, expensive material are required for efficient light absorption and charge collection. Furthermore, silicon does not absorb in the infrared, a spectral region that contains about a quarter of the sun's radiation. In this talk, I will discuss non-equilibrium laser-doping techniques we have been developing in the Mazur group that attempt to... Read more about Extending silicon's reach: nonequlibrium doping using ultrafast lasers

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