McCall Research Group Illinois

Dr. Brian Brumfield

Benjamin McCall
June 15, 2011 - 4:51 PM

Brian Brumfield recently defended his PhD thesis!

On June 6, Brian Brumfield successfully defended his PhD dissertation, entitled "Development of a Quantum Cascade Laser Based Spectrometer for High-Resolution Spectroscopy of Gas Phase C60."

Brian's thesis work involved the design and construction of a novel type of mid-infrared spectrometer. This spectrometer is intended to enable the first high-resolution infrared spectroscopy of C60. C60 is an interesting spectroscopic target, both because of its large size and high symmetry, but also because it has been recently detected (by low-resolution emission spectroscopy) in planetary nebulae using the Spitzer space telescope. The only transition of C60 that is accessible to ground-based telescopes is at a frequency (~1185 cm-1) outside the range of all commercially available cw lasers. Brian's work involved establishing a collaboration with the group of Claire Gmachl at Princeton, which develops quantum cascade lasers (QCLs) at new frequencies. Brian successfully integrated a QCL with a cavity ringdown spectrometer, and performed the first true "spectral discovery" with a QCL, using a vibrational band of methylene bromide (CH2Br2). Together with Jacob Stewart, he also developed a novel supersonic slit source and high temperature oven that enables spectroscopy of rotationally cold samples of molecules with low vapor pressure. As a first step towards C60, he and Jacob recorded the rotationally resolved spectrum of pyrene (C16H10), which is the largest molecule ever detected using high-resolution absorption spectroscopy! The hunt for the spectrum of C60 is being continued by Jacob Stewart and Brad Gibson.

In July, Brian will begin a postdoctoral position in the group of Professor Gerard Wysocki in the Electrical Engineering department at Princeton. In the Wysocki group, Brian plans to leverage his background in chemistry and spectroscopy to extend the use of QCLs to real-world applications, using advanced techniques such as Faraday rotation spectroscopy. Our group is also planning a collaboration with the Wysocki group to apply external-cavity QCLs to cavity ringdown spectroscopy, so we anticipate continued close ties to Brian. We wish Brian all the best in his next career step!