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Superradiance on the millihertz linewidth strontium clock transition
Matthew A Norcia1, Matthew N Winchester1, Julia R K Cline1
1JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO 80302, USA.
Science Advances
|October 21, 2016
Summary
Researchers created a superradiant laser using strontium atoms, enhancing atomic clock stability. This novel approach overcomes limitations from laser frequency noise and cavity fluctuations for more precise timekeeping.
Area of Science:
- Atomic, Molecular, and Optical Physics
- Quantum Optics
- Metrology
Background:
- Laser frequency noise and reference cavity length fluctuations limit the precision of current atomic clocks.
- Superradiant lasers offer a potential solution by acting as active atomic clocks with enhanced stability.
- Utilizing atomic clock transitions as gain media is a promising avenue for improved clock performance.
Purpose of the Study:
- To demonstrate and characterize superradiant emission from a millihertz linewidth optical clock transition.
- To investigate the collective enhancement of emission rates in a laser-cooled strontium atom ensemble.
- To explore seeding methods and interference phenomena for characterizing superradiant lasers.
Main Methods:
- Trapping laser-cooled 87Sr atoms in a high-finesse optical cavity.
- Generating and measuring superradiant emission from the atomic ensemble.
- Employing seeding techniques and observing interference between simultaneous lasing subensembles.
Main Results:
- Observed superradiant emission from the 87Sr millihertz linewidth clock transition.
- Measured a collective emission rate enhancement exceeding 10,000 times compared to independent emission.
- Demonstrated seeding of superradiant emission and used interference to characterize spectral properties.
Conclusions:
- Superradiant lasers based on atomic clock transitions can significantly improve atomic clock performance.
- The collective enhancement observed offers a pathway to more stable and precise optical clocks.
- Interference measurements provide a novel method for characterizing the spectral properties of superradiant lasers.
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