Formation of ultracoldX1Σ+(v′′=0)NaCs molecules via coupled photoassociation channel

Direct photoassociative formation of ultracold KRb molecules in the lowest vibrational levels of the electronic ground state

“…This phenomenon has been observed in Rb 2 [12], Cs 2 [13], RbCs [14] and is theoretically predicted for many heteronuclear dimers [15]. In NaCs [10], this phenomenon is believed to lead the formation of molecules in the rovibronic ground state. In our present work, we have discovered a pair of states in KRb that are resonantly coupled, the 2(1) and 4(1) states.…”

“…The presence of a large molecule-fixed electric dipole moment in the absolute rovibrational ground state (v ′′ = 0, J ′′ = 0) makes external control over the motion and internal quantum state very convenient, opening up the fields of ultracold chemical reactions and collisions [3], many body physics [4] and quantum computation [5]. To date, polar molecules in the v = J = 0 level of the ground state have been successfully achieved by 1) magnetoassociation or photoassociation (PA) followed by stimulated Raman transfer in KRb [6,7] and RbCs [8] and 2) photoassociation followed by direct radiative decay in LiCs [9] and NaCs [10]. Although the first technique can efficiently transfer a selectively prepared sample of vibrationally excited ultracold molecules to the lowest rovibronic level, the appeal of the second technique is that it provides a simple, single-step, continuous and irreversible process for converting ultracold atoms into molecules in the lowest rovibronic level.…”

Two-photon photoassociation spectroscopy of an ultracold heteronuclear molecule

“…There has been immense interest and progress in creating ultracold heteronuclear polar molecules [1][2][3][4][5][6][7][8][9][10][11][12] which, by virtue of their permanent electric dipole moment in the electronic ground state, are important for a variety of experiments not possible with ultracold atoms [13][14][15][16]. One-photon photoassociation (PA) of ultracold atoms [17] has been extensively used to create ultracold diatomic molecules in excited electronic states [12] and in many cases such molecules spontaneously decay to the electronic ground state [3,[18][19][20][21][22]. While this has been a successful strategy even for the formation of rovibronic ground state i.e.…”

“…While this has been a successful strategy even for the formation of rovibronic ground state i.e. X 1 Σ + ( = 0) molecules of some species [3,20,21], the process always leads to molecules being formed in a distribution of vibrational and rotational states [18][19][20][21][22]. An alternative approach is to again start with ultracold atoms but use a coherent coupling scheme for the formation of molecules in a specific rovibronic state.…”

Luminorefrigeration of NaCs

“…Then, there is the efficient but technically challenging demonstration of magneto-association and coherent transfer of KRb [16] to the rovibrational ground state using a laser system referenced to a frequency comb. Also, direct photoassociation yields rovibrational ground state LiCs [17] and vibrational ground state NaCs [18] but with the majority of the sample distributed across a range of excited rovibrational states.…”