How To Get to Know 200 Students (Almost) Overnight, at American Association of Physics Teachers Winter 2000 Meeting (Kissimmee, FL), Monday, January 17, 2000:
Direct interaction between students and teacher is essential to effective teaching. Unfortunately, it is often lacking in large classes. We have developed a system which facilitates efficient asynchronous communication between teacher and students. Students' questions are stored in a database, and the contents of the database are accessed via the Web in various forms. For example, the teacher can review all student questions on a particular topic, prepare a single answer to a common question, and store the answer in the database. Students' grades and pictures are stored with their questions (... Read more about How To Get to Know 200 Students (Almost) Overnight
Peer Instruction: Getting Students to Think in Class, at 1999 Sigma Xi Forum (Minneapolis, MN), Thursday, November 4, 1999:
Most introductory undergraduate science courses are taught in large lectures. Although an efficient use of instructor time, passive lectures rarely challenge students to think critically in class, often reinforcing the common expectation that learning science amounts to acquiring information. Many students respond by memorizing facts or formulas without understanding the fundamental concepts. To actively engage students during class and focus their attention on underlying concepts, we have developed a student-centered approach to teaching large courses, Peer Instruction. Lectures are... Read more about Peer Instruction: Getting Students to Think in Class
Femtosecond laser micromachining of bulk glass at oscillator energies, at Gordon Conference on Nonlinear Optics, Colby Sawyer College (New London, NH), Tuesday, July 27, 1999:
Using femtosecond laser pulses generated by a 25-MHz Ti:Sapphire laser oscillator, we micromachine bulk glass. The laser is focused by a 1.4 numerical aperture microscope objective, allowing the breakdown threshold to be reached with modest energies (4.5 nJ). Single-shot damage is sub-micron in size. Because the pulses arrive faster than energy can diffuse out of the focal volume, multiple shot damage with this laser is thermal in nature. Successive pulses add more and more heat to the sample, melting a micron-sized volume. Using this thermal machining, we have written single-mode waveguides... Read more about Femtosecond laser micromachining of bulk glass at oscillator energies
Molecular orientation in Langmuir monolayers studied by surface second harmonic generation, at APS Centennial Meeting 1999 (Atlanta, GA), Tuesday, March 23, 1999:
We used surface second harmonic generation (SHG) to study molecular orientation in a smectic-C liquid-crystal Langmuir monolayer at an air/water interface. The molecules under investigation are 4-octyl-4'-(3-carboxytrimenthyleneoxy) azobenzene (8AZ3). Because water is inversion symmetric, the SHG signal comes only from the surface. Furthermore, the magnitude of the surface SHG signal depends on the orientation of molecules, which makes SHG a sensitive probe of the phase of the monolayer. We measured the response of the SHG signal as we compressed the monolayer from a smectic-C phase to a more... Read more about Molecular orientation in Langmuir monolayers studied by surface second harmonic generation
Microexplosions: Highly supersonic plasma expansion following femtosecond laser induced breakdown, at OSA Annual Meeting (Baltimore, MD), Thursday, October 1, 1998:
Tightly focused ultrashort laser pulses are used to produce a hot, dense plasma in water. Using time-resolved imaging and scattering techniques we map the supersonic expansion of this plasma. The expansion reaches a speed of 90 km/s, the fastest expansion witnessed to date in laser induced breakdown. Extreme temperature and pressure drive this expansion.