A physicist associated with research on laser cooling. His NIST account explains how measured atomic temperatures fell below the limit predicted by a simple Doppler cooling model. The discrepancy led to a more detailed explanation involving atomic internal states and spatially varying light polarization, including Sisyphus cooling. The episode shows why measuring the velocity distribution was essential: a model adequate for slowing an atomic beam did not capture all the processes operating in an optical cooling experiment.[ref]
Observation of Atoms Laser-Cooled Below the Doppler Limit by Steven Rolston. Historical account: time-of-flight temperature measurements, failure of the simple Doppler limit and polarization-gradient explanation
New to topics? Read the docs here!