Miranda Claypool

Major: Physics
Mentors: Dr. Antonin Sojka, Professor Mark Sherwin

Beam Waist Finder For Improvement Of Electron Paramagnetic Resonance Spectroscopy Accuracy

Electron Paramagnetic Resonance (EPR) Spectroscopy utilizes the Zeeman effect to analyze samples containing unpaired electrons. The Zeeman effect splits the energy levels of an electron’s spin when in a magnetic field. When these electrons absorb a radiation beam of a similar energy as the split, they emit a photon which can be measured. This technique uses high energy, high frequency radiation, which is provided by the ITST’s Free Electron Laser and requires many quasioptical elements to redirect the laser and the emitted photon to their destinations. Even miniscule errors in the alignment of these optical elements can propagate and cause huge losses in accuracy.

Our research this summer was to develop an efficient way to find the focal point of the curved focusing mirrors in the setup, and the width of the reflected beam at the focal point ‚Äì the beam waist. To do this, we created a mobile setup that scans along the mirror‚Äôs axis, taking pictures of the beam as it‚ Äôs reflected onto a vertical plane. These images are analyzed using the Python library OpenCV and the Hough Transform to find the point where the beam is smallest, which corresponds to the focal length. This will improve the alignment of the Sherwin Group‚Äôs novel EPR Spectrometer.