Colloquium

The Tyranny of the Lecture: Confessions of a converted lecturer, at Enrico Fermi Colloquium, European Laboratory for Non-Linear Spectroscopy Seminar, Universitá di Firenze (Florence, Italy), Friday, July 19, 2013:
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
Nonlinear optics at the nanoscale, at University of Virginia (Charlottesville, VA), Friday, April 12, 2013:
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
The scientific approach to teaching: Research as a basis for course design, at Physics Colloquium, Boston University (Boston, MA), Tuesday, January 22, 2013:
Discussions of teaching -- even some publications -- abound with anecdotal evidence. Our intuition often supplants a systematic, scientific approach to finding out what works and what doesn't work. Yet, research is increasingly demonstrating that our gut feelings about teaching are often wrong. In this talk I will discuss some research my group has done on gender issues in science courses and on the effectiveness of classroom demonstrations.
Educating the Innovators of the 21st Century, at University of Pretoria (Pretoria, South Africa), Friday, June 1, 2012:
Can we teach innovation? Innovation requires whole-brain thinking — left-brain thinking for creativity and imagination, and right-brain thinking for planning and execution. Our current approach to education in science and technology, focuses on the transfer of information, developing mostly right-brain thinking by stressing copying and reproducing existing ideas rather than generating new ones. I will show how shifting the focus in lectures from delivering information to team work and creative thinking greatly improves the learning that takes place in the classroom and promotes independent... Read more about Educating the Innovators of the 21st Century
Black silicon, at Physics Colloquium, University of Pretoria (Pretoria, South Africa), Thursday, May 31, 2012:
Shining intense, ultrashort laser pulses on the surface of a crystalline silicon wafer drastically changes the optical, material and electronic properties of the wafer. The resulting textured surface is highly absorbing and looks black to the eye. The properties of this 'black silicon' make it useful for a wide range of commercial devices. In particular, we have been able to fabricate highly-sensitive PIN photodetectors using this material. The sensitivity extends to wavelengths of 1600 nm making them particularly useful for applications in communications and remote sensing.
The make-believe world of real-world physics, at Physics Colloquium, Massachusetts Institute of Technology (Cambridge, MA), Thursday, May 17, 2012:
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?
Reinventing the light switch: logic with photons, at Physics Colloquium, University of Massachusetts, Lowell (Lowell, MA), Wednesday, April 25, 2012:
Future computers and communications systems will require extremely fast logic operations that cannot be achieve efficiently using electronics. By using nonlinear optical materials with nano-scale structuring, we will show how to replace these “slow” electrons with photons to achieve logic operations on an ultrafast time scale.
Confessions of a converted lecturer, at Physics Colloquium, Northeastern University (Boston, MA), Thursday, April 5, 2012:
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 Special Laser Seminar / NCCR MUST Seminar, ETH Zürich (Zürich, Switzerland), Thursday, February 23, 2012:
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
Confessions of a converted lecturer, at The Zurich Physics Colloquium, ETH Zürich (Zürich, Switzerland), Wednesday, February 22, 2012:
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

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