Franck-Condon Tuning of Optical Cycling Centers by Organic Functionalization

Functionalizing Aromatic Compounds with Optical Cycling Centers

“…Further, the vibrational branching ratios (VBRs) were determined and regardless of the choice of ligand it was found that > ∼ 90% of the pho- ton scattering events did not change the vibrational state of the molecule. Small variation in the VBR, at the few percent level, was observed, and found to be consistent with a theoretical calculation suggesting that pK a provides a simple guide for designing ligands with the best OCC performance [13]. From this work, we found that CaO--345F does not change its vibrational state during roughly 99% of scattering events, implying that laser cooling is possible with current technology.…”

“…This suggests that the alkaline-earth(I)-oxygen moiety can be considered as a functional group, akin to an alcohol or ether. Subsequent bonding of this functional group to electron withdrawing ligands should therefore allow scattering of many photons without changing the vibrational state of the resulting molecule [13,14].…”

“…Molecular species were first identified via 2D spectroscopy, performed by scanning the OPO frequency and recording the DLIF. Transitions between the ground ( X 2 A 1 ) and two lowest-energy electronic states ( A 2 B 2 and B 2 B 1 ) have been predicted to have potential for laser cooling [13] due to the localization of the molecular orbitals on the Ca atom (see Fig. 1(b)), and are therefore the targets of this work.…”

Magneto-Optical Trapping and Sub-Doppler Cooling of a Polyatomic Molecule

“…This is particularly notable as recent theoretical and experimental work indicates that these criteria are satisfied not only by linear, triatomic molecules, but also by several classes of molecules of even greater structural complexity. Several candidate species have already been identified, spanning nonlinear symmetric top molecules (e.g., CaOCH 3 , SrOCH 3 ) [2], asymmetric top molecules (e.g., CaSH, CaNH 2 ) [57], and complex organic molecules containing carbon rings (e.g., CaOC 6 H 5 , SrOC 9 H 2 F 9 ) [3,58].…”

Accurate prediction and measurement of vibronic branching ratios for laser cooling linear polyatomic molecules

“…Laser cooling of polyatomic molecules, however, is more challenging. To understand the difficulty, this key metric should be considered -the quasidiagonality of the Franck-Condon matrix for the electronic laser cooling transition [31][32][33][34][35][36] In order to quantify this metric, and thus determine whether a molecular candidate can be successfully loaded and held in a MOT, knowledge of all decays with intensity above about 10 −5 is needed to ensure that a sufficient number of photons may be scattered by each molecule. Recent observations of nominally symmetry-forbidden decays [37,38] confirm that very weak decays, which can only be observed with considerable effort, can pose major obstacles to achieving an optical cycle capable of scattering > 10 4 photons per molecule.…”