Terahertz Sum-Frequency Excitation of a Raman-Active Phonon

Evolution of anatase surface active sites probed by in situ sum-frequency phonon spectroscopy

Surface active sites of crystals often govern their relevant surface chemistry, yet to monitor them in situ in real atmosphere remains a challenge. Using surface-specific sum-frequency spectroscopy, we identified the surface phonon mode associated with the active sites of undercoordinated titanium ions and conjoint oxygen vacancies, and used it to monitor them on anatase (TiO2) (101) under ambi...

Terahertz - frequency magnon - phonon - polaritons in the strong coupling regime

Strong coupling between light and matter occurs when the two interact strongly enough to form new hybrid modes called polaritons. Here we report on the strong coupling of both the electric and magnetic degrees of freedom to an ultrafast terahertz (THz) frequency electromagnetic wave. In our system, optical phonons in a slab of ferroelectric lithium niobate (LiNbO3) are strongly coupled to a THz...

Anharmonicity on Raman active phonon modes of LaAlO3

Coherent two-dimensional terahertz-terahertz-Raman spectroscopy.

We present 2D terahertz-terahertz-Raman (2D TTR) spectroscopy, the first technique, to our knowledge, to interrogate a liquid with multiple pulses of terahertz (THz) light. This hybrid approach isolates nonlinear signatures in isotropic media, and is sensitive to the coupling and anharmonicity of thermally activated THz modes that play a central role in liquid-phase chemistry. Specifically, by ...

Resonant Raman Scattering from Iodine: Spectral Changes with Excitation Frequency