Molecule project

Igor Mourachko, Simon Cornish, and Ifan Hughes

We are building a new experiment to make ultracold molecules from rubidium and caesium cold atoms using shaped femtosecond pulses. This is in collaboration with Gareth Roberts' group at Newcastle, and Ian Walmsley's group at Oxford. The work is supported by by the EPSRC grant EP/D502594/1.

Cold Cs atoms!
Dan and Anna celebrate commissioning the Cs laser system and obtaining a Cs MOT. Two lasers are needed for laser cooling of Cs (and Rb); these and the spectroscopy set-up for frequency stabilization, were constructed on portable breadboards at Durham, and then transported to the laboratory at Newcastle.
Chamber built!
The vacuum chamber has been assembled and baked-out. The pressure is currently in the low 10^(-10) Torr regime. The chamber has 12 ports in the horizontal plane.
TOF constructed
The time-of-flight mass spectrometer has been assembled. As explained below, there are two different electric fields which are realised with six separate rods. A time-dependent sequence of voltages on these rods will accelerate the molecular ions towards the detector, whilst the atomic ions are deflected.
TOF principle
A time-of-flight mass spectrometer has been designed. Most TOF spectrometers separate the atomic and molecular signals in time. Our colleagues at Oxford informed us that a potential issue is that the atomic ions arrive at the detector earlier than the molecules of interest - although the species of different charge-to-mass ratio are clearly resolved in time, the detector can be blinded by the much larger atomic signal. This motivated us to design a two-field spectrometer. Our spectrometer will offer both high resolution and excellent optical access to the MOT in the entire horizontal and one vertical plane. This design uses six independent rod electrodes and allows both the time focusing of the ions and deflection of the atomic ions.
Optical Table arrives in Newcastle
Our experiment will have two principal parts: a vacuum chamber where cold Rb and Cs atoms are made at temperatures of the order of one hundred microKelvin in a Magneto-Optical Trap (MOT); and a shaped femtosecond pulse source. In addition we need four lasers to make the atoms cold in the first place; the femtosecond pulses need to be generated, amplified and shaped; and we need some detection lasers. To fit all of this in there is an optical table in the laboratory at Newcastle which is 6m long.

Publications arising from this project

Content © Ifan Hughes, Durham University 2007. Last updated April 22 2009.