The innovation engine for new materials

Samuel Gebretsadkan

Samuel Gebretsadkan

Major: 

Physics

Mentor(s): 

Mingyu Fan

Faculty Sponsor(s): 

Andrew Jayich

Faculty Sponsor's Department(s): 

Physics

Project Title: 

Pulsed Laser Intensity Stabilization for Radium Ion Clocks

Project Description: 

Optical clocks use electronic transitions in atoms as a reference frequency, allowing for higher precision when measuring time than current microwave frequency methods. They will enable us to track time for the Global Positioning System more accurately and study how physics laws such as Einstein's relativity vary in outer space. Radium ions are a strong candidate for optical clocks as they can be laser cooled and have a narrow line-width S1/2 to D5/2 transition. Due to its heavy mass, radium significantly reduces some of the clock's inherent systematic errors; also, it is one of the most sensitive to probing deviations of time-dependent fundamental constants such as the gravitational constant. We utilize a Paul trap-based optical clock with a 728 nm laser that tracks the optical clock transition frequency in Ra-226 to record time. For an optical clock to function properly, the intensity of light that drives different transitions must be nearly constant. To maintain stable light intensity, we created a feedback loop apparatus that can pulsate a laser beam while stabilizing its power. By applying pulsed stabilization to the radium ion clock, we improve precise control of the radium ions and enhance the performance of a radium ion optical clock.