International Journal of Molecular Sciences (Dec 2020)

Infrared Comb Spectroscopy of Buffer-Gas-Cooled Molecules: Toward Absolute Frequency Metrology of Cold Acetylene

  • Luigi Santamaria,
  • Valentina Di Sarno,
  • Roberto Aiello,
  • Maurizio De Rosa,
  • Iolanda Ricciardi,
  • Paolo De Natale,
  • Pasquale Maddaloni

DOI
https://doi.org/10.3390/ijms22010250
Journal volume & issue
Vol. 22, no. 1
p. 250

Abstract

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We review the recent developments in precision ro-vibrational spectroscopy of buffer-gas-cooled neutral molecules, obtained using infrared frequency combs either as direct probe sources or as ultra-accurate optical rulers. In particular, we show how coherent broadband spectroscopy of complex molecules especially benefits from drastic simplification of the spectra brought about by cooling of internal temperatures. Moreover, cooling the translational motion allows longer light-molecule interaction times and hence reduced transit-time broadening effects, crucial for high-precision spectroscopy on simple molecules. In this respect, we report on the progress of absolute frequency metrology experiments with buffer-gas-cooled molecules, focusing on the advanced technologies that led to record measurements with acetylene. Finally, we briefly discuss the prospects for further improving the ultimate accuracy of the spectroscopic frequency measurement.

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