Laser-controlled rotational cooling of Na2 based on exceptional points
Abstract
Exceptional points (EPs) corresponding to resonance coalescence (i.e., complex energy degeneracy and identical wave functions) occur in many areas of non-Hermitian physics and, in particular, in laser-induced molecular dynamics for specific choices of two control parameters. We have previously shown [Atabek, , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.106.173002 106, 173002 (2011)] how these control parameters, namely, the wavelength and the intensity of the external field, have to be tuned to take advantage of EPs for selective vibrational transfers within a reduced one-dimensional model describing a diatomic molecule with frozen rotation. Moreover, the possibility offered by such transfers to adiabatically transport all the vibrational population to the ground v=0 level has been presented as a realistic vibrational cooling strategy with an entropy flow toward the field-induced dissociative channel. The purpose of the present article is twofold: (i) Extend the model to a full three-dimensional quantum description of the rotating molecule and discuss the existence, determination, and role of EPs involving rovibrational resonances; (ii) examine the possibility for a further challenging step in obtaining ultracold molecules through combined vibrational and rotational laser control dynamics, aiming at total purification for reaching the ground (v=J=0) rovibrational level. The illustrative example is the Na2 molecule for which translationally cold species have experimentally been obtained.
- Publication:
-
Physical Review A
- Pub Date:
- September 2013
- DOI:
- 10.1103/PhysRevA.88.033408
- Bibcode:
- 2013PhRvA..88c3408K
- Keywords:
-
- 37.10.Mn;
- 37.10.Pq;
- 33.80.Gj;
- 42.50.Hz;
- Slowing and cooling of molecules;
- Trapping of molecules;
- Diffuse spectra;
- predissociation photodissociation;
- Strong-field excitation of optical transitions in quantum systems;
- multiphoton processes;
- dynamic Stark shift