Towards charge transfer or Sisyphus cooling of molecules (using ro-vibrational cooling)

Martin Zeppenfeld, Barbara G. U. Englert, Rosa Glöckner +6 more

M. Hamamda, P. Pillet, Hans Lignier +1 more

By using a simple spectral shaping technique, optical pumping with laser fields has allowed us to manipulate, on demand, the rotational and vibrational population of di-atomic molecules. We review this method developed first on cold Cs 2 then on ions and discuss its extension to other molecular species as well as its feasibility on a molecular beam. This paves the way to the production of brighter molecular beams and thus a new method of producing cold molecular cloud. We finally present some ideas based on Sisyphus cooling with expected results on neutral as well as ionic molecules.

John F. Barry, David P. DeMille

R. Horchani

The possibility of controlling all the motion as well as the internal quantum state of a sample of molecules is a long term goal in the cold molecules field. Although many different techniques have been used to produce ultra-cold molecules, in this paper, we will concentrate on the optical pumping technique successfully used to achieve rotational and vibrational cooling of Cs2molecules. We will review the different photo-association schemes for molecule formation, the detection schemes through photoionization, the ro-vibrational cooling into a single level and finally the electronic conversion. In addition, we will present a theoretical model for both ro-vibrational cooling and electronic conversion that can be used for the preparation of different experiments.

Tomasz Urbańczyk, J. Koperski

Method of ro-vibrational cooling of Cd2 and Yb2 molecules occupying initially their excited ro-vibrational levels in the ground electronic state is proposed. The method employs the c31u(53P2)↔X10g+(51S0) and 30u+(63P1)↔X10g+(61S0) electronic transitions in Cd2 and Yb2, respectively. The cooling relies on a successive decrease of population of the ground-state vibrational υ″ and rotational J″ levels using a series of laser-induced excitations from a selected ground-state (υ″, J″) to the excited-state (υ′=υ″−1, J′=J″−1) ro-vibrational levels, followed by spontaneous de-excitations to the ground state. The proposal is an extension of the vibrational cooling method recently proposed by Urbańczyk et al. [Mol. Phys. 116, 3475–3486 (2018)].

Jesús Pérez‐Ríos