Presentations

    Wrapping light around a hair, at Physics Colloquium, University of Alaska Fairbanks (Fairbanks, AK), Friday, October 29, 2010:
    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
    The Social Learning Network: Advancing Student Learning in the Social Sciences using Peer Instruction, You Don't Get to Subject-Matter Understanding Without Making a Few Friends First, at Cognition, Brain & Behavior Colloquium, CUNY - Brooklyn College (Brooklyn, NY, USA), Wednesday, February 16, 2011
    How can I help my students learn in ways that pique their interest and enrich their subject matter understanding? In this Colloquium, we will explore this perennial question by considering an innovative, research-based teaching method called Peer Instruction (PI). Originally developed by Eric Mazur to address major gaps in students' conceptual knowledge of physics at Harvard University, this interactive pedagogical method is now widely used in classrooms at hundreds of institutions across the world. PI leverages the power of social learning and the latest advances in instructional technology... Read more about The Social Learning Network: Advancing Student Learning in the Social Sciences using Peer Instruction, You Don't Get to Subject-Matter Understanding Without Making a Few Friends First
    Nonlinear optics at the nanoscale, at Physics Colloquium, Lehigh University (Bethlehem, PA), Thursday, April 28, 2011:
    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
    Memorization or understanding: are we teaching the right thing?, at Physics Department Colloquium, Queen's University (Kingston, ON, Canada), Friday, November 11, 2011:
    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?
    Memorização ou compreensão: estamos ensinando o certo?, at Physics Colloquium, Universidade Federal de Pernambuco (Recife, PE, Brazil), Friday, January 27, 2012:
    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 Memorização ou compreensão: estamos ensinando o certo?
    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
    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 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
    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.
    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?
    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.
    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
    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.
    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 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
    Subcellular surgery and nanosurgery, at Neils Colloquium for Innovative Science, Valparaiso University (Valparaiso, IN), Friday, November 1, 2013:
    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
    Educating the Innovators of the 21st Century, at United States Military Academy (West Point, NY), Thursday, April 3, 2014:
    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
    Educating the Innovators of the 21st Century, at Oregon State University (Corvallis, OR), Thursday, May 15, 2014:
    Can we teach innovation? Innovation requires whole-brain thinking — right-brain thinking for creativity and imagination, and left-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
    Why you can pass tests and still fail in the real world, at Portland Community College Sylvania (Portland, OR), Thursday, May 15, 2014:
    Why is it that stellar students sometimes fail in the workplace while dropouts succeed? One reason is that most, if not all, of our current assessment practices are inauthentic. Just as the lecture focuses on the delivery of information to students, so does assessment often focus on having students regurgitate that same information back to the instructor. Consequently, assessment fails to focus on the skills that are relevant in life in the 21st century. Assessment has been called the "hidden curriculum" as it is an important driver of students' study habits. Unless we rethink our approach to... Read more about Why you can pass tests and still fail in the real world

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