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Presentation |
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We are developing a two-photon spectroscopy
experiment of the vibrational levels of the molecular ion H2+.
The aim of the experiment is to measure the fundamental vibration
frequency, and to deduce from it the proton to electron mass ratio,
with a comparable or smaller relative uncertainty with respect to the most
precise present determinations. Ion trap We have built a radiofrequency ion trap
(Paul trap). The RF is about 10.7 MHz, the trap depth is a few eV. The trapped ions can be extracted from the
trap and the ion species can be distinguished by time-of-flight
measurement.
Piège
à ions, zone de temps de vol et détecteur MCP
State
selection of the ions An excimer laser (KrF at 248 nm) will be used for selective photodissociation of ions in the vibrational levels v>0, allowing to prepare an ion cloud in the v=0 state.
Excitation
of the two-photon transition The two-photon transition between bound
states of H2+ will be excited by a Quantum
Cascade Laser (QCL) diode at 9.128 microns. The interest of this source
is that it is tunable and yields a cw power of the order of 50 mW. |
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