Clarisse, Nicolas

Photodetector Construction and Characterization for a Short-Range Gravity Search Experiment

My name is Nicolas Clarisse and I am a graduating senior at DePaul. Following graduation, I will be a first year graduate student in physics at the University of Illinois – Urbana-Champaign this fall. My interest in this thesis topic stemmed from my fascination with table-top physics experiments that can be used to probe at fundamental questions in physics and has since evolved into studying quantum information science which is my planned research area at UIUC. Outside of academics, I enjoy rock climbing, weightlifting, and food! While at DePaul, I was an active member of DePaul’s math, rock-climbing, and astrophysics clubs.

Major: Physics

Minor: Chemistry

Senior, College of Science and Health

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Abstract

Experiments that probe nature’s fundamental forces at the smallest length scales require highly sensitive and precise detectors. To better understand gravity at the sub-micron level, a photodetector was built for use in an experiment in which a 300-nm diameter silica bead is suspended in an optical dipole trap (l = 1064 nm) and then transferred to an optical cavity (l = 1596 nm) while a test mass of varied density is oscillated at a known frequency at a distance of 1 μm under high vacuum. The light scattered off the silica bead while in the dipole trap impinges upon two quadrant InGaAs photodiodes, which provide highly precise data for the location of the bead in real time in all three spatial dimensions. Upon transforming the time series data to a frequency domain, information about the gravitational attraction between the bead and the oscillating test mass can be obtained while the bead is suspended near the test mass in the optical cavity. The detection bandwidth of the photodetectors themselves were characterized in preparation for integration into the larger experimental setup.

Thesis Director: Dr. Andrew Geraci

Northwestern University, Department: Physics and Astronomy

Faculty Reader: Dr. Timothy French

DePaul University, Department: Chemistry

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Project Poster

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