2014/08/31 by Philip G. Westergaard, Bjarke T. R. Christensen, David Tieri +7 · 31 citations
Physics and Astronomy · #Advanced Fiber Laser Technologies #Advanced Frequency and Time Standards #Atomic physics #Classical mechanics #Cold Atom Physics and Bose-Einstein Condensates #Dispersion (optics) #Laser #Laser linewidth #Materials science #Motion (physics) #Nonlinear optical #Nonlinear optics #Nonlinear system #Optical cavity #Optics #Physics #Quantum mechanics #physics.atom-ph
paper · pdf · doi:10.1103/physrevlett.114.093002
published in Physical Review Letters 114(9), 093002 (American Physical Society) · 9 pages (including 4 pages of Supplemental Information), 6 figures. Updated to correspond to the published version
openalex publication_date 2015/03/04 · arxiv created 2015/04/20 · arxiv updated 2015/04/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
As an alternative to state-of-the-art laser frequency stabilization using ultrastable cavities, it has been proposed to exploit the nonlinear effects from coupling of atoms with a narrow transition to an optical cavity. Here, we have constructed such a system and observed nonlinear phase shifts of a narrow optical line by a strong coupling of a sample of strontium-88 atoms to an optical cavity. The sample temperature of a few mK provides a domain where the Doppler energy scale is several orders of magnitude larger than the narrow linewidth of the optical transition. This makes the system sensitive to velocity dependent multiphoton scattering events (Dopplerons) that affect the cavity field transmission and phase. By varying the number of atoms and the intracavity power, we systematically study this nonlinear phase signature which displays roughly the same features as for much lower temperature samples. This demonstration in a relatively simple system opens new possibilities for alternative routes to laser stabilization at the sub-100 mHz level and superradiant laser sources involving narrow-line atoms. The understanding of relevant motional effects obtained here has direct implications for other atomic clocks when used in relation to ultranarrow clock transitions.