Creating ultra-cold molecules by sympathetic cooling
Lead Research Organisation:
University College London
Department Name: Physics and Astronomy
Abstract
Laser cooling has been of primary importance in the exploration of ultra-cold interactions between trapped atoms, for quantum atom optics, and for precision metrology through high-resolution spectroscopy. It has also provided a well-controlled testing ground for condensed matter physics, and more recently quantum information. Attention has now turned to molecules because of the quite different interactions that can occur between ultra-cold molecules. They are seen as ideal candidates in the search for CPT violation, for exploring ultra-cold chemistry, and for the creation of novel quantum fluids using dipolar molecules. Unfortunately, laser cooling, which has been so successful for many atomic species cannot be applied to molecules and thus new methods are required to reach this new regime in molecular and ultra-cold physics. This proposal aims address this problem by utilising the very general techniques of sympathetic and evaporative cooling to create ultra-cold molecules from cold stationary molecules that have been created by optical Stark deceleration. To undertake this work we will bring ultra-cold laser cooled xenon atoms into thermal contact with stationary cold molecules initially at temperatures in the 10 mK to 1 K range. We will use elastic collisions between the cold xenon atoms and the molecules co-trapped within an optical field to thermalise the mixture, bringing it to a common temperature below the 1 mK bottleneck that currently exists. Although in principle sympathetic and evaporative cooling are applicable to many molecular species, this project will explore the cooling of molecular hydrogen and benzene by collisions with ultra cold xenon, producing molecules in the 100 microkelivn temperature range and below. An important part of this programme will be the study, via experiment and theory, the atom-molecule collisions that are vitally important for sympathetic and evaporative cooling, as well as for the potential ultra-cold molecular chemistry that can be studied once the molecules are cooled into the microkelvin temperature regime. This research will utilise our optical Stark decelerator and will build a magneto-optical trap for producing ultra-cold xenon atoms. We will also build a deep optical trap that will be capable of holding atomic or molecular species for the long periods (seconds) required for thermalisation.
Publications
Zhao Y.
(2009)
Optical cavity cooling of a large ensemble of molecules
in 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009
Zhao Y
(2009)
Self-organisation and cooling of a large ensemble of particles in optical cavities.
in Faraday discussions
Barker PF
(2009)
Sympathetic cooling by collisions with ultracold rare gas atoms, and recent progress in optical Stark deceleration.
in Faraday discussions
Bishop A
(2010)
Creating cold stationary molecular gases by optical Stark deceleration
in New Journal of Physics
Gerakis A
(2011)
Coherent Brillouin scattering.
in Optics express
Gerakis A
(2013)
Single-shot coherent Rayleigh-Brillouin scattering using a chirped optical lattice.
in Optics letters
Purcell SM
(2009)
Tailoring the optical dipole force for molecules by field-induced alignment.
in Physical review letters
Edmunds PD
(2014)
Trapping cold ground state argon atoms.
in Physical review letters
Douglas P
(2012)
Frequency stabilization of an external-cavity diode laser to metastable argon atoms in a discharge
in Review of Scientific Instruments
Edmunds PD
(2013)
A deep optical cavity trap for atoms and molecules with rapid frequency and intensity modulation.
in The Review of scientific instruments
Description | This successful project developed the tools required for sympathetic cooling cold molecules. Twenty one publications resulted from this work and the main results are summarised in these papers. The work included theoretical research which modeled cold collisions between laser cooled atoms and molecules as well as computer codes that modeled these collision processes in optical were developed. A setup to laser cool argon atoms was built and and the deep optical trap for cold atoms and molecules was constructed. In addition, a method for laser acceleration of neutral particles was developed. |
Exploitation Route | Exploitation via academic publishing. |
Sectors | Aerospace, Defence and Marine,Education,Other |
Description | Our findings have been used towards further understanding how molecules can be manipulated using optical fields. |
Sector | Other |
Impact Types | Societal |
Description | Collaboration with Princeton University |
Organisation | Princeton University |
Country | United States |
Sector | Academic/University |
PI Contribution | Experimental support of a number of programmes |
Collaborator Contribution | Theoretical support |
Impact | Publications across a range of grants. |