Angela Ludvigsen

Biography

Learning is my passion and the study of physics truly inspires me. It is my goal to successfully complete my undergraduate studies in physics and math at the University of Wisconsin River Falls (UWRF) and then to earn a PhD in Physics. My long term plan is to join a university, doing research and teaching. I am very proud to be the first person in my family to pursue an advanced degree in science.

I discovered my research interests while still in high school at St Paul Central in Minnesota. I interned with Science Research Institute (SRI) for a year working on a water quality project at Northwestern University. I learned to perform chemical analysis on water samples and then, with my team, presented our findings at local area high schools. After working on a research paper in nuclear power plant shielding and successfully completing two years of high school physics classes, I realized I truly enjoyed physics and wanted to make the study of physics my life work.

While I am truly driven to be a respected scientist, I do have other aspects to my life. At UWRF, I tutor Math and Physics, joined Math Club, volunteered a semester as a Chancellor's Student Ambassador, and am serving as secretary of the UWRF chapter of the Society of Physics Students. I worked as a lifeguard and a swim instructor for St. Paul Community Education. Additionally, I captained the Central High School Girls' Dive Team and still volunteer at a number of charities I first served in my high school years.

Project abstract

A laser can be used as an optical trap to catch and hold small, transparent objects. Observations of optically trapped aqueous aerosol droplets have demonstrated that the droplet moves between two or more stable positions dependent upon the power of the trapping laser. It is hypothesized that this movement coincides with a resonance between the trapping light and the droplet’s surface, called a Whispering Gallery Mode. When this resonance occurs, forces acting on the droplet cause it to move. To investigate this behavior, Raman scattered light from the droplet as well as the droplet’s position are measured. The Raman spectrum exhibits a series of peaks resulting from the droplet’s spherical shape, referred to as Cavity Enhanced Raman Spectroscopy (CERS). The location and spacing of these peaks are known to be related to the diameter and the optical properties of the droplet. From this spectrum, the magnitude of the electric and magnetic fields of the scattered light are calculated. This allows for a precise measurement of the droplet’s radius at the moment that the droplet moves between stable positions. After determining the droplet’s radius from the spectrum, the effect of varying the intensity of the trapping laser beam on the droplet radius can be investigated.