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arXiv · 1602.08303

Terahertz-visible two-photon rotational spectroscopy of cold OD-

Seunghyun Lee·Daniel Hauser·Olga Lakhmanskaya·Steffen Spieler·Eric S. Endres·Katharina Geistlinger·Sunil S. Kumar·Roland Wester
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Abstract

We present a method to measure rotational transitions of molecular anions in the terahertz domain by sequential two-photon absorption. Ion excitation by bound-bound terahertz absorption is probed by absorption in the visible on a bound-free transition. The visible frequency is tuned to a state-selective photodetachment transition of the excited anions. This provides a terahertz action spectrum for just few hundred molecular ions. To demonstrate this we measure the two lowest rotational transitions, J=1<-0 and J =2<-1 of OD- anions in a cryogenic 22-pole trap. We obtain rotational transition frequencies of 598596.08(19) MHz for J=1<-0 and 1196791.57(27) MHz for J=2<-1 of OD-, in good agreement with their only previous measurement. This two-photon scheme opens up terahertz rovibrational spectroscopy for a range of molecular anions, in particular for polyatomic and cluster anions.

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Seunghyun Lee, Daniel Hauser, Olga Lakhmanskaya, Steffen Spieler, Eric S. Endres, Katharina Geistlinger, Sunil S. Kumar, Roland Wester. 2016-02-26. Terahertz-visible two-photon rotational spectroscopy of cold OD-. https://doi.org/10.1103/physreva.93.032513

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