Second-Generation Laser Experiments in Undergraduate Laboratories

Bemidji State University, Bemidji MN

Investigators

Abstract

Chemistry (12) While lasers (helium-neon, nitrogen, and dye lasers) have been used in undergraduate pedagogy to conduct first-generation laser experiments, the availability of Nd:YAG lasers, with high pulse energy and superior beam quality, have paved the way for second-generation laser experiments. The departments of chemistry and physics are taking the vital step of incorporating second generation laser experiments into the laboratory curriculum by using Nd:YAG lasers. Six advanced laser experiments are being introduced initially as research projects and later, as regular experiments, into the laboratory courses (physical, organic and inorganic chemistry and optics). These experiments are adapted from both recent educational sources (e.g. Journal of Chemical Education) and from the research literature. The integrated use of Nd:YAG, YAG pumped dye lasers and a FTIR spectrometer facilitates a wide range of advanced experiments for undergraduates, covering the areas of gas-phase, non-linear, and low-temperature spectroscopy. The experiments include stimulated Raman scattering (SRS) of hydrogen, deuterium, nitrogen and oxygen; coherent anti-Stokes Raman (CARS) scattering of air; time-resolved laser-induced fluorescence (LIF) of OH radicals in flame; low-temperature matrix assisted photolysis (LTMAP) of organometallics; photoreduction of benzophenone; and conventional Raman (CRS) and IR spectroscopy of organic molecules. Most of them use a computer interface, a boxcar averager and a pre-amplifier along with a monochromator and a photomultiplier tube to scan, collect and analyze the spectral data. This exposes students to advanced lasers and to computer-based data acquisition techniques in a non-black box learning environment. Collectively, these experiments upgrade the optics laboratory (physics) and enhance the curriculum in physical, organic, and inorganic chemistry and optics courses.