2012 BFY Abstract Detail Page
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||Lasers and Optics open-ended projects at Bethel University
||We describe three open-ended lab projects developed in upper-level courses by students at Bethel University. We also describe laser cooling research that integrates several open-ended projects.
In the first highlighted project, students constructed an external cavity diode laser that is tunable over several nanometers about a central wavelength of 633 nm for use in iodine spectroscopy. Using saturated absorption techniques, they observed saturation dips corresponding to the hyperfine components within a Doppler-broadened feature. The second project comprised a small, simple Michelson interferometer that was used to measure the index of refraction of air, argon, carbon dioxide, sulfur hexafluoride, and helium. Students measured n-1 of air, CO2, Ar and SF6 with a relative uncertainty of nearly 10^-3, which was limited by the uncertainty in cell length. The third highlighted project demonstrated quantum optics by using an argon ion laser to create pairs of 915.8 nm correlated photons through spontaneous parametric down-conversion. One of the photons was sent through a Mach-Zehnder interferometer to realize single-photon interference. The coherence lengths of a single photon were measured when long-pass and 10-nm bandpass filters were placed before the avalanche photo diode used to detect the photons.
Student researchers recently realized a lithium magneto-optical trap of ~10^7 atoms with a temperature of ~500 microkelvin. This research project is a collaboration of students over the past several years and has integrated multiple open-ended projects from Lasers, Optics, and Senior Research courses. These include a sub-picometer wavemeter, external cavity diode lasers, and characterization of a semiconductor tapered amplifier.
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3900 Bethel Dr. 2336
Sarah Venditto, Dan Mohr, Andrew Stephan