A repository & source of cutting edge news about emerging terahertz technology, it's commercialization & innovations in scanners, quality control, process control, medical diagnostics, security, astronomy,communications, graphene, metamaterials, CMOS, compressive sensing,3d printing, and the Internet of Everything. NOTHING POSTED IS INVESTMENT ADVICE! REPOSTED COPYRIGHT IS FOR EDUCATIONAL USE. I am a private investor in THz.
Tuesday, March 22, 2016
Abstract-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, and Roland Wester
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 a 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 598 596.08(19) MHz for J=1←0 and 1 196 791.57(27) MHz forJ=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.