Raman scattering from the effective soft mode in lead germanate crystal

Горелик, В. С.; Pyatyshev, A. Yu.

doi:10.1002/jrs.5854

Cited by 6 publications

(3 citation statements)

References 46 publications

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“…Since the Fourier spectrum was obtained in this case for a second‐order process (second‐harmonic (SH) intensity), it should be taken into account that this peak actually corresponds to a frequency of about 1 THz (≈32.7 cm −1 ), which coincide to the soft mode of LG (32.9 cm −1 ) at room temperature. [ 16,17 ]…”

Section: Figurementioning

confidence: 99%

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Transient Polarization Reversal using an Intense THz Pulse in Silicon‐Doped Lead Germanate

Bilyk

Мишина

Sherstyuk

et al. 2020

Physica Rapid Research Ltrs

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The processes of dynamic polarization switching induced by the strong electric field of a nearly single‐cycle terahertz (THz) pulse are studied in a classical ferroelectric silicon‐doped lead germanate single crystal, Pb5(Ge0.74Si0.26)3O11, in THz pump–second‐harmonic‐generation (SHG) probe geometry depending on the pulse electric field strength (0.05–15.6 MV cm−1). Since the pump parameters correspond to the region of phonon excitations for a given material, THz‐induced polarization is explained by a dynamic change in the ferroelectric order parameter. Numerical solutions of the Landau–Khalatnikov equation using the thermodynamic potential constants for this material show that the effect of powerful THz pulses leads to polarization modulations and a strong nonlinear response, and is in good agreement with the experimental results. Oscillations of the nonlinear optical response after the end of the THz pulse are found, which can be associated with the excitation of the phonon mode in the crystal.

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Section: Figurementioning

confidence: 99%

“…The problem is related to the fact that the THz pulse affecting on the system is rather wide and covers both the soft and optical A TO modes, including strong IR + Raman active mode at 70.7 cm −1 . [ 16,17 ]…”

Section: Figurementioning

confidence: 99%

Transient Polarization Reversal using an Intense THz Pulse in Silicon‐Doped Lead Germanate

Bilyk

Мишина

Sherstyuk

et al. 2020

Physica Rapid Research Ltrs

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“…мягкая мода. До последнего времени для исследования некогерентных процессов в этой области применялась методика спектроскопии комбинационного рассеяния [3,4].…”

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Dispersion of optical constants of Si:PbGeO crystal in the terahertz range

Bilyk

Brekhov

Агранат

et al. 2023

Rossijskij tehnologičeskij žurnal

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Objectives. Advances in laser physics over the last decade have led to the creation of sources of single-period electromagnetic pulses having a duration of about 1 ps, corresponding to the terahertz (THz) frequency range and a field amplitude of several tens of MV/cm. This allows the electrode-free application of an electric field to a ferroelectric for observing not only the excitation of coherent phonons, but also ultrafast (at the sub-picosecond timescale) dynamic polarization switching. To detect polarization switching, a pump-probe technique is used in which a THz pulse is used with an optical probe. Since its intensity is proportional to the square of the polarization, the signal of the optical second harmonic is used to measure polarization switching under the action of a THz pulse. To evaluate switching efficiency, both linear (refractive index and absorption coefficient) and non-linear optical characteristics (quadratic and cubic susceptibilities) are required. For any application of ferroelectric crystals in the THz range, knowledge of the relevant linear optical characteristics is also necessary.Methods. The technique of THz spectroscopy in the time domain was used; here, a picosecond THz pulse transmitted through the crystal is recorded by strobing the detector with a femtosecond optical pulse. The THz-induced dynamics of the order parameter in a ferroelectric was studied by detecting the intensity of a nonlinear optical signal at the frequency of the second optical harmonic.Results. The transmission of a THz wave and the intensity of second harmonic generation on a lead germanate crystal doped with silicon in the time and spectral domains were measured. On this basis, the absorption coefficient dispersion and cubic nonlinear susceptibility were calculated in the range of 0.5-2.0 THz. The presence of a region of fundamental absorption near the phonon modes was confirmed along with a resonant enhancement of the cubic nonlinear susceptibility for two phonon modes Ω1 = 1.3 THz and Ω2 = 2.0 THz.Conclusions. The proposed technique is effective for analyzing the dispersion of the optical characteristics of ferroelectric crystals. The significantly improved spectral resolution (0.1 THz) increases the accuracy of determining nonlinear susceptibility due to the detailed analysis of the linear and nonlinear contributions to the second harmonic intensity.

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Raman and Hyper Raman opalescence on the soft mode in barium sodium niobate crystals

Горелик

Pyatyshev

2020

Optical Materials

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Raman scattering from the effective soft mode in lead germanate crystal

Cited by 6 publications

References 46 publications

Transient Polarization Reversal using an Intense THz Pulse in Silicon‐Doped Lead Germanate

Transient Polarization Reversal using an Intense THz Pulse in Silicon‐Doped Lead Germanate

Dispersion of optical constants of Si:PbGeO crystal in the terahertz range

Raman and Hyper Raman opalescence on the soft mode in barium sodium niobate crystals

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