2009

Black silicon, at Huang Kun Forum on Semiconductor Sciences and Technologies, Institute of Semiconductors, Chinese Academy of Sciences (Beijing, China), Tuesday, December 22, 2009:
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, remote sensing, and photovoltaics.
Nonlinear optics at the nanoscale, at Seminar, Institute of Semiconductors, Chinese Academy of Sciences (Beijing, China), Tuesday, December 22, 2009:
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 10,000 Women Faculty Development Program, Harvard University (Cambridge, MA), Monday, December 14, 2009:
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?
How the mind tricks us: visualizations and visual illusions, at Jefferson Lab Science Series, Jefferson Laboratory (Newport News, VA), Wednesday, December 9, 2009:
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
Confessions of a converted lecturer, at Workshop and Open Forum, Jefferson Laboratory (Newport News, VA), Wednesday, December 9, 2009:
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
Peer Instruction Workshop, at Videoconference, Escuela Politécnica Nacional de Ecuador (Cambridge, MA), Thursday, December 3, 2009:
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
Optical Hyperdoping; Using lasers to tailor the optoelectronic properties of semiconductors, at 2009 Fall MRS Meeting: Ultrafast Materials Science Symposium (Boston, MA), Wednesday, December 2, 2009:
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.
Gender, interactive teaching, and barriers to change, at Women in Science and Engineering Workshop, Thomas Jefferson National Accelerator Facility (Newport News, VA), Monday, November 16, 2009:
Can pedagogy alleviate the well-known "gender gap" in performance and representation in the physical sciences? I will show that women can succeed on par with male students in introductory classes that are taught cooperatively, rather than competitively. At the same time we found that the level of perceived confusion increases in classes that challenge every student to think about and respond to questions asked during class. This increase is a potential barrier to reform even though we have shown it to anti-correlate with performance.
Peer Instruction, at Faculty Development Center Workshop, University of Maryland Baltimore County (Baltimore, MD), Thursday, November 12, 2009:
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
Peer Instruction Workshop, at New Physics and Astronomy Faculty Workshop, American Center for Physics (College Park, MD), Thursday, November 12, 2009:
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

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