Probing Hyperfine Transitions in Gaseous Rb with Doppler-Free Spectroscopy
presented by Tristan Carlson C'20
Wednesday, March 27, 7:30 - 8:30pm, Woods Labs 216
Absorption spectroscopy is employed in a diverse collection of fields to identify the atomic makeup of materials. Saturated absorption spectroscopy, also known as Doppler-free or diode-laser spectroscopy, is a high-resolution spectral technique that can be used to probe hyperfine transitions in atoms. The key components of the system are a tunable laser, counter-propagating pump and probe beams of the same frequency, and a gas cell. The anti-parallel pump and probe beams effectively select atoms with no movement parallel to the beam path, eliminating Doppler broadening. These hyperfine transitions arise from the nuclear spin of the rubidium atoms. In this talk, I will describe how I use a 384,000 GHz diode laser with a very narrow linewidth to probe the hyperfine structure of gaseous rubidium isotopes, resolving spectral features as narrow as 0.01 GHz. I have also constructed a Fabry-Perot interferometer to establish a relative frequency scale, and I am currently exploring magnetic field and temperature effects on the rubidium absorption spectrum.
Tristan Carlson, C’20, is a junior physics major from Alpharetta, Georgia. He is a member of the Chi Psi fraternity and a former member of the Sewanee men’s soccer team. Tristan is a member of the national physics honor society Sigma Pi Sigma and the past vice-president of Sewanee’s Society of Physics Students. In the past two years, he has competed in the international University Physics competition ranking as an accomplished competitor and silver medalist. Tristan has done research in Dr. Donev’s lab on lithographic fabrication of silver nanostructures for surface-enhanced Raman spectroscopy, and at the University of Alabama at Birmingham on energy transfer in mid-infrared laser gain materials and photoinduced modification of their refractive index. His work at UAB resulted in a first-author publication and he will be presenting it at the CLEO 2019 conference. He continues his optics-related research this summer at Oak Ridge National Laboratory, where he will work in the field of quantum optics.