Angular Dependent Fluorescence of Different Gasses

REU Student: David Hensle

Supervisor:  Dr. Vinod Kumarappan

Research Project

Dr. Kumarappan, in the broadest sense, develops experimental methods to align and orient molecules using femtosecond laser pulses.  My project focuses on light that is emitted from these aligned molecules to better understand the process of alignment dependent fluorescence of different gasses.


In order to learn about the process of alignment dependent fluorescence, my project was to build an imaging spectrometer.  By acquiring the spectrometer data along with existing alignment dependent experiments, we hope to better understand the process of how the molecules produce the light, whether it is through tunnel ionization of lower lying orbitals, or molecular excitement.


The imaging spectrometer takes a picture of the laser focus (which is aligning the molecules), and for each wavelength of light that is being emitted from the focus, an image appears on the camera at a particular horizontal direction. By calibrating camera pixel number to wavelength, we can determine both the energy level transition that emitted the photon and where in the laser focus the ionization is occurring (since the camera takes a picture of the laser focus).


The summer project of designing, building, and aligning the spectrometer was accomplished. A spectrum from plasma generated in air was taken and well defined lines showed up on the camera.  See the Final Presentation tab for a more detailed report.