Colloquium

How the mind tricks us: visualizations and visual illusions, at SLAC Colloquium, Stanford Linear Accelerator Center (Menlo Park, CA), Monday, October 9, 2006:
Neurobiology and cognitive psychology have made great progress in understanding how the mind processes information – in particular visual information. The knowledge we can gain from these fields has important implications for the presentation of visual information and student learning.
Subcellular surgery and nanosurgery, at Sigma Pi Sigma Colloquium, University of Connecticut (Storrs, CT), Friday, April 28, 2006:
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
Wrapping light around a hair, at Physics Colloquium, Northwestern University (Evanston, IL), Friday, November 18, 2005:
Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was ‘no’. We developed a technique for drawing long, free-standing silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a high uniformity of diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it... Read more about Wrapping light around a hair
Subcellular surgery and nanoneurosurgery, at A Year of Physics Colloquium, North Carolina A&T State University (Greensboro, NC), Thursday, November 10, 2005:
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 nanoneurosurgery
Memorization or understanding: are we teaching the right thing?, at A Year of Physics Teaching/Learning Workshop, North Carolina A&T State University (Greensboro, NC), Thursday, November 10, 2005:
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 Memorization or understanding: are we teaching the right thing?
Wrapping light around a hair: optics at the nanoscale, at Physics Colloquium, Arizona State University (Tempe, AZ), Thursday, October 13, 2005:
Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was ‘no’. We developed a technique for drawing long, free-standing silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a high uniformity of diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it... Read more about Wrapping light around a hair: optics at the nanoscale
Wrapping light around a hair: manipulating light at the nanoscale, at Physics Colloquium, University of Washington (Seattle, WA), Monday, October 10, 2005:
Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was ‘no’. We developed a technique for drawing long, free-standing silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a high uniformity of diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it... Read more about Wrapping light around a hair: manipulating light at the nanoscale
Visualizations and visual illusions: how the mind tricks us, at Center for Astrophysics Lecture, Harvard University (Cambridge, MA), Tuesday, January 11, 2005:
Neurobiology and cognitive psychology have made great progress in understanding how the mind processes information – in particular visual information. The knowledge we can gain from these fields has important implications for the presentation of visual information and student learning.
Wrapping light around a hair, at Physics Colloquium, University of Missouri-Rolla (Rolla, MO), Thursday, October 21, 2004:
Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was ‘no’. We developed a technique for drawing long, free-standing silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a high uniformity of diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it... Read more about Wrapping light around a hair
Wrapping light around a hair, at Physics Colloquium, University of Massachusetts Lowell (Lowell, MA), Wednesday, September 22, 2004:
Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was ‘no’. We developed a technique for drawing long, free-standing silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a very uniform diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it possible to... Read more about Wrapping light around a hair

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