Will Yelle -- Studies of Transparent Conducting Oxides

Advisor: Professor Nelson

Transparent conducting oxides (TCO's) are materials that are rare in that they are both conductive (almost metallic) and transparent, and are therefore extremely useful for such applications as solar cells and computer screens. Will is working with samples of two such TCO.'s: ZnGeInO and ZnGaInO. Since the presence of oxygen atoms in these materials actually inhibits conduction, then the conductivity can be enhanced by annealing them in a reducing atmosphere, that is, one that removes oxygen atoms from the lattice. Will is trying to determine the effects that this annealing will have on the samples.

Brian Stenger -- Design of a Wavemeter for Measuring Laser Wavelengths

Advisor: Professor Tate

Brian is designing a wavemeter, a device which will be used to measure the wavelength of laser radiation to great accuracy. For instance, the human eye can distinguish seven wavelengths (red - violet) in the visible spectrum. In contrast, the wavemeter will be able to distinguish at least a half million different wavelengths (colors) in the visible spectrum. This project involves making workshop plans using a computer, and building interference-fringe counting electronics, and assembling and aligning optical components.

Jeffrey Wenzel -- Transformation coefficients for Photometric Data

Advisor: Professor Campbell

Transformation coefficients allow astronomers from many places and using different equipment to combine their photometric data (from medium band width filters) into one light curve. These coefficients transform the data to conform to the standard system. Using obsevations of M67, an open cluster, Jeffrey is determining these coefficients by both the Macintosh application IPLab and the more accurate Image Reduction and Analysis Facility (IRAF). Calculating these coefficients will allow students and faculty to compare their data taken at Colby's observatory to the standard data published by the American Association of Variable Star Observers (AAVSO).

Rob Sutter -- Single Bubble Sonoluminescence

Advisor: Professor Conover

Rob is building an apparatus which will produce a sonoluminescing bubble. The phenomenon is called single bubble sonoluminescence or SBSL for short. It consists of oscillating a flask of degassed water using sound generated by transducers, a wave function generator, and an amplifier. Some scientists have hypothesized that the energy of the bubble might stretch into the x-ray regime. The bubbles are thousands of Kelvins hot when they collapse. They last about a picosecond and occur with a fair regularity. SBSL might at some point be used for studying fusion as an alternative to using powerful lasers.

Adrian Calder -- Scanning Tunneling Microscope

Advisor: Professor Nelson

Adrian is working with the scanning tunneling microscope (STM). Theories of tip fabrication have been explored as one of the important factors of optimal use. The function of the STM is based on quantum mechanics and the tunneling of a current between a conducting surface and the platinum iridium (or tungsten) tip. The force current is controlled by a PID feedback circuit as the tip scans the topography of the surface. The height of the tip and the potential differences between the tip and sample allow the surface to be plotted. Scans of gold gratings and graphite sample have been taken, and the results have allowed us to view actual carbon atoms.

Deirdre Foley -- Atomic Force Microscopy

Advisor: Professor Nelson

Deirdre is working on atomic force microscopy (AFM). Deirdre is using the AFM to better understand the surface topology of organic conducting polymers deposited on a silicon substrate. Her main effort is in trying to correlate surface features with the electrical properties of the polymers.

Erik Gustavson -- Measuring Temperatures in the Sub-Polar Mesopause

Erik worked this past summer with the Space Physics/Optics group at the Geophysical Institute of the University of Alaska in Fairbanks. He worked using a Bomem-Michelson Interferometer to record the spectra of atmospheric emissions given off during twilight. By processing this spectra and determining the characteristic lines emitted by hydroxyl (OH) radicals in the mesopause (approx. 86 km) it is possible to determine the temperature by creating Boltzmann plots for the Meinel OH 3,1 band. Due to overshadowing of the OH emission by solar radiation, it is then possible to find an exact temperature. The measured temperature fell in the range of 120 deg. K to 180 deg. K, which is compatible with current theory.

John Mendez -- Atoms in Strong Fields

Advisor: Professor Conover

John is constructing a broadband laser to use studying both the dynamics of atoms and the interaction of atoms with strong light fields. The broadband laser can excite an atom to more than one state at a time: a quantum mechanical superposition state. Following the excitation, a second identical laser pulse redistributes the population. John is performing experiments using sodium in a molecular beam: a simple model system. The broadband dye laser he is building is a modification of a standard design allowing multimode broadband operation.