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Updated: May 7, 2026

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Frequency renormalization and its effects in nonlinear phononics withQRQIR2-type coupling
1College of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China.
Abstract:
A two-phonon system with lowest-order coupling of formQRQIR2is studied by perturbation method, and analytic results for both phonon displacements and frequencies are obtained. The frequency renormalization of infrared (IR) active mode brings the rectification of Raman mode to saturate at high pump field. For degenerate IR mode with coupling of formQR(QIR,x2-QIR,y2), the frequency of IR mode will split when resonantly pumped by elliptically or linearly polarized ultrashort mid-IR pulse, realizing Raman rectification and magnetization simultaneously. Our results reveal a dynamical effect of nonlinear phononics not captured by first-principles calculation, extend the dynamical multiferroicity to systems with couplingQR(QIR,x2-QIR,y2), and the method can be readily applied to higher-order couplings. The amplitude saturation under strong pump field stimulates future researches to overcome this nonlinear effect.
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