Quantum-interference-enhanced deep sub-Doppler cooling of 39K atoms in gray molasses
Abstract
We report enhanced sub-Doppler cooling of the bosonic atoms of 39K facilitated by formation of dark states with the cooling and repumping lasers tuned to the Raman resonance in Λ configuration near the D1 transition. A temperature of about 12 μK and phase-space density >2×10-5 is achieved in the two-stage D2-D1 molasses and spans a very large parameter region where quantum interference persists robustly. We also present results on enhanced radiation heating with a subnatural linewidth (0.07Γ) and a signature Fano-like profile of a coherently driven three-level atomic system. The optical Bloch equations relevant for the three-level atom in a bichromatic light field are solved with the method of continued fractions to show that cooling occurs only for a small velocity class of atoms, emphasizing the need for precooling in the D2 molasses stage.
- Publication:
-
Physical Review A
- Pub Date:
- November 2013
- DOI:
- 10.1103/PhysRevA.88.053407
- arXiv:
- arXiv:1305.5480
- Bibcode:
- 2013PhRvA..88e3407N
- Keywords:
-
- 37.10.De;
- 32.80.Wr;
- 67.85.-d;
- Atom cooling methods;
- Other multiphoton processes;
- Ultracold gases trapped gases;
- Physics - Atomic Physics;
- Quantum Physics
- E-Print:
- 7 pages,10 images