Abstract-Direct Frequency-Comb-Driven Raman Transitions in the Terahertz Range

C. Solaro, S. Meyer, K. Fisher, M. V. DePalatis, M. Drewsen,

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.253601

We demonstrate the use of a femtosecond frequency comb to coherently drive stimulated Raman transitions between terahertz-spaced atomic energy levels. More specifically, we address the $3d{2D}_{3/2}$and $3d{2D}_{5/2}$ fine structure levels of a single trapped $40{\mathrm{Ca}}^{+}$ ion and spectroscopically resolve the transition frequency to be ${\nu }_D=1,819,599,021,534\pm 8\mathrm{Hz}$. The achieved accuracy is nearly a factor of five better than the previous best Raman spectroscopy, and is currently limited by the stability of our atomic clock reference. Furthermore, the population dynamics of frequency-comb-driven Raman transitions can be fully predicted from the spectral properties of the frequency comb, and Rabi oscillations with a contrast of 99.3(6)% and millisecond coherence time have been achieved. Importantly, the technique can be easily generalized to transitions in the sub-kHz to tens of THz range and should be applicable for driving, e.g., spin-resolved rovibrational transitions in molecules and hyperfine transitions in highly charged ions.

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Abstract-The new concept of nano-device spectroscopy based on Rabi-Bloch oscillations for THz-frequency range

Ilay Levie, and Gregory Slepyan

https://arxiv.org/ftp/arxiv/papers/1706/1706.10014.pdf


We considered one-dimensional quantum chains of two-level Fermi particles coupled via the tunneling driven both by ac and dc fields in the regimes of strong and ultrastrong coupling. The frequency of ac field is matched with the frequency of the quantum transition. Based on the fundamental principles of electrodynamics and quantum theory, we developed a general model of quantum dynamics for such interactions. We showed that the joint action of ac and dc fields leads to the strong mutual influence of Rabi- and Bloch oscillations one to another. We focused on the regime of ultrastrong coupling, for which Bloch- and Rabi-frequencies are a significant values of the frequency of interband transition. The Hamiltonian was solved numerically with account of anti-resonant terms. It manifests by the appearance of great number of narrow high-amplitude resonant lines in the spectra of tunneling current and dipole moment. We proposed the new concept of THz spectroscopy promising for different applications in future nanoelectronics and nano-photonics.