Raman spectroscopy and X-Ray analysis of non-stoichiometric lithium niobate crystals

Сидоров, Н. В.; Teplyakova, N. А.; Palatnikov, M. N.; Алешина, Л. А.; Sidorova, O.V.; Kadetova, A. V.

doi:10.1016/j.jssc.2019.121109

Cited by 5 publications

(2 citation statements)

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“…[26][27][28][29] However, the LiNbO 3 crystal presents a significant challenge due to the intricate nature of its excited-state resonant bonds and phonon spectra, which are usually accompanied by intense nonlinear signal radiation. [30] Although second harmonic phase-sensitive measurements and transient detection of specific phonon amplitude changes have been achieved experimentally, [14,31,32] these techniques are insufficient to investigate the mesoscopic transient dynamics of the lattice, such as the lattice deformation.…”

Section: Introductionmentioning

confidence: 99%

“…The electron-phonon coupling effect induces an ordered modulation on the anisotropic lattice, resulting in the activation of the anharmonic phonon mode (A 1 -TO 4 ), which is present as the active vibrational mode in Raman spectra. [14,30] The displacement excitation of this mode leads to oriented forces (stress) in the oxygen octahedra (NbO 6 ), forcing oriented lattice strain. We observe the transient dynamic evolutions of lattice-induced lattice contraction/expansion under varying excitation levels in less than 1 ps.…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast Multistage Lattice Strain via Laser‐Excited Phonons in Lithium Niobate

Wu,

Yang,

Zhang

et al. 2023

Advanced Optical Materials

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Ultrafast laser‐excitation of lithium niobate (LiNbO3) crystal has triggered numerous photonic applications through the structural transitions in LiNbO3. However, the explanations for ultrafast laser‐induced modification of LiNbO3 have remained phenomenological, lacking a convincing in‐depth understanding of the fundamental laser‐lattice interaction process. Based on ab initio simulations, it is demonstrated that photoexcited anharmonic phonons play a significant role in influencing the lattice structure of LiNbO3. Harnessing the real‐time time‐dependent density functional theory, it is revealed that the excitation of TO4 phonons via electric‐phonon coupling triggers displacement‐induced lattice oscillations during multiphoton ionization. These oscillations give rise to multistage structural strains, resulting in alterations of the refractive index. Significantly, these modifications exhibit sensitivity to the incident laser energy. Experimentally, using the waveguide technique and micro‐Raman spectroscopy, the correlation between local refractive index, lattice volume density, and phonon vibrational modes has been established, exhibiting good consistency with theoretical predictions. This work provides an effective means to understand the ultrafast excitation of phonons and relaxation processes of the lattice in dielectric crystals.

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