Frontiers in Optics

State-selective Detection of Ultracold Rb2 and Optical Trapping Using a CO2 Laser

Hyewon Pechkis, Yanyan Huang, Dajun Wang, C. Ashbaugh, Edward E. Eyler, P. L. Gould, William C. Stwalley

Published Jan 1, 2006• 0 citations

Abstract

We report formation and state-selective detection of ultracold Rb2 by photoassociation. Resonance-enhanced ionization was used for the detection. We also present recent progress towards forming ultracold Rb2 in an optical trap using a CO2 laser.

DOI: 10.1364/ls.2006.ltue5

Related papers

Formation, detection and spectroscopy of ultracold Rb2in the ground X1Σg+state

Yanyan Huang, J Qi, Hyewon Pechkis +4 more

We form ultracold ground-state Rb 2 molecules by photoassociating pairs of atoms in a magneto-optical trap into the 0 u + state, which decays radiatively into high vibrational levels of the X 1 Σ g + state. Sensitive and vibrationally state-selective detection is achieved by means of resonantly-enhanced two-photon ionization with a pulsed laser. Frequency scans of the detection laser reveal a long vibrational progression to a previously unobserved electronic excited state, which we identify as the 2 1 Σ u + state. Most of its vibrational spectrum is in excellent agreement with predictions based on ab initio potentials, although the lowest vibrational levels exhibit strong perturbative mixing with the triplet 2 3 Π u state. The detection method reported here, with minor variations, should be effective for the entire potential well of the X state. In this work no transitions are observed from vibrational levels above v = 118, but this turns out to be a limitation not of the detection method but rather of the photoassociative formation scheme, due to re-excitation of the highest- v levels by the same photoassociation laser that produces them.

Journal of Physics B Atomic Molecular and Optical PhysicsSep 25, 200652 citations

Formation, Detection and Trapping of Photoassociated Ultracold KRb Molecules

Dajun Wang, J. Qi, M. F. Stone +7 more

Ultracold ground-state KRb molecules are formed by photoassociation and detected by resonant two-photon ionization. We have assigned both the photoassociation spectrum and the detection laser spectrum, and we have demonstrated magnetic trapping of triplet KRb

Quantum Electronics and Laser Science ConferenceDec 10, 20051 citation

Utlracold Rb2 Molecules: Formation, Detection and Trapping in an Optical Dipole Trap

Hyewon Pechkis

This thesis comprises two topics in the field of the ultracold atomic and molecular physics, both involving formation of ultracold 85Rb 2 by photoassociation (PA). Typically, these ground-state molecules are formed mainly in the very highest vibrational levels, rather than the low-v levels that will be required for most future investigations of ultracold molecular physics and chemistry. The first topic of my research is a method for circumventing this problem: resonant enhancement (RE) of photoassociative ground-state molecule production. The key idea of RE is to photoassociate pairs of colliding atoms into an excited state that has a bimodal vibrational probability distribution, with one peak at long range to enhance the photoassociation rate and another at shorter range to enhance radiative decay into deeply bound levels of the ground state. This can be arranged thanks to the strong spin-orbit perturbative interaction between the two 0+u states converging to two different asymptotes, (5s + 5p1/2) and (5s + 5 p3/2). This method enhances ground-state molecule formation in the region well below the dissociation limit. The experimental work described here was done at the University of Connecticut in collaboration with C. P. Koch at the Institut für Theoretische Physik, Freie Universität Berlin, Germany, who performed the theoretical analysis [1].^ The second part of my thesis is the investigation of ultracold molecules in an optical dipole trap. We have constructed a quasi-electrostratic optical trap (QUEST) for 85Rb using a focused CO2 laser [2]. This provides a very high density of ultracold atoms, up to 10 12 cm-3, providing much higher photoassociation rates. It also keeps the molecules trapped once they have formed. The QUEST provides an ample trapping lifetime for both trapped atoms and molecules, yielding about 4-5×106 atoms and about 9×105 high-v molecules. The long lifetime of the trapped molecules and atoms, combined with their high density, allows us to study interactions such as atom-molecule or molecule-molecule collisions in the ultracold regime. A preliminary experiment on Rb2 molecular decay is described. ^

Jan 1, 20100 citations

Photoassociative Formation, Spectroscopic Detection, and Magnetic Trapping of Ultracold KRb Molecules

Edward E. Eyler, Dajun Wang, P. L. Gould +1 more

We report on formation and state-selective detection of ultracold polar KRb molecules, and on magnetic trapping of the metastable a state. Resonant two-photon ionization spectra are analyzed to map the electronic structure and vibrational distributions.

Frontiers in OpticsJan 1, 20050 citations

Production, detection and trapping of ultracold molecular rubidium

Yiyan Huang

Production and state-selective detection of ultracold molecular rubidium (85Rb2) in the singlet ground state and the metastable triplet state are described. Ultracold 85Rb2 molecules are produced via photoassociation followed by radiative decay. State-selective detection of high-ν ground-state and metastable-state molecules is carried out by resonant Two-photon ionization (R2PI) with a pulsed laser. The spectra of both the ground singlet and metastable triplet states are investigated. Spectroscopy of several intermediate excited states, some of which are observed for the first time, is also studied. Mixing between excited singlet and triplet states is observed in both the singlet and triplet spectra. A proposal for producing ν = 0 ground-state molecules by utilizing this singlet-triplet mixing is given. Magnetic trapping and filtering of metastable triplet-state molecules is also described, and a scheme for optical trapping of molecules is proposed.^

Jan 1, 20064 citations

Spectroscopy of Na2 by photoassociation of laser cooled Na

L. P. Ratliff, Mark E. Wagshul, Paul D. Lett +2 more

Recently, several groups,1-4 have used photoassociation of ultracold atoms to study transitions from free atoms to bound molecules. Photoassociative spectroscopy involves illuminating a collection of laser cooled and trapped atoms with a tunable probe laser. When the probe laser is resonant with transition to an excited molecular state, molecules are formed and detected either by ionizing the molecules or by monitoring changes in the number of trapped atoms.

May 8, 19944 citations