milliHertz Linewidth Continuous Superradiant Laser

We are working to realize an ultra-low noise laser in which the phase information of the laser is hidden in a collective state of strontium atoms that are laser cooled and trapped inside of a high finesse optical cavity.  In previous work, we were able to observe pulses of superradiantly emitted light from the long-lived milliHertz strontium clock transition.  The center frequency of the pulses of light was nearly a million times less sensitive to cavity noise than traditional approaches and had a fractional frequency stability of 7 x 10^-16.  This first-of-its-kind pulsed laser has inspired us to develop a continuous with a quantum-limited linewidth of a milliHertz or less.  Such a laser that would enable next-generation searches for dark matter, geodesy based on general relativity, and atomic clocks.

Strontium Ring Cavity System

We have successfully built a ring cavity in which atoms can be loaded in one region and then transported in a light conveyor belt to a region where the atoms will undergo superradiant lasing.  If successful, we believe fractional frequency stabilities at or below 5 x 10^-18 at one second may be obtainable.