https://doi.org/10.1051/epjconf/202328707017
Mid-IR frequency laser control with a comb for H2+ spectroscopy
1 Laboratoire Kastler Brossel, Sorbonne Université, ENS, CNRS ; 4 place Jussieu, Case 74, 75005 Paris, France
2 Département de Physique, Univ EVRY Université Paris Saclay, rue du père André Jarlan, 91025 Evry, France
* Corresponding author: laurent.hilico@lkb.upmc.fr
Published online: 18 October 2023
We will report our recent progress toward H2+ spectroscopy by use of a SI-referenced Mid-IR source laser. H2+ molecular ions are very interesting candidates to improve the determination of fundamental constants, such as the proton to electron mass ratio mp/me and search for new physics beyond the standard model. At LKB, an erbium fibered frequency comb is phase locked to the LNE-SYRTE frequency standards thanks to the T-REFIMEVE network. By sum frequency generation in a AgGaSe2 crystal between a CO2 laser and an output of the comb at 1895 nm, a shifted frequency comb centered at 1560 nm is generated. The latter is then mixed with the original one to generate a beatnote used to stabilise the Mid-IR laser. As a first application, a narrow saturated absorption line in formic acid has been extensively studied. Pressure, power and modulation depth shifts and broadenings have been evaluated, leading to a determination of its central frequency at a sub ppt (10-12) resolution, high enough for H2+ spectroscopy and fundamental constant determination.
© The Authors, published by EDP Sciences, 2023
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