Perturbed free induction decay in ultrafast mid-IR pump–probe spectroscopy

Yan, Suxia; Seidel, Marco T.; Tan, Howe‐Siang

doi:10.1016/j.cplett.2011.10.013

Cited by 26 publications

(26 citation statements)

References 20 publications

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“…Figure 6a shows examples of the oscillatory signals we observe. The oscillations start at negative time delays when the probe pulse arrives at the sample before the excitation pulse, suggesting that the probe pulse generates a coherence that the excitation pulse interacts with, as observed in perturbed free-induction decays45565758. However, the periods of the oscillations we observe are insensitive to probe frequency or pump pulse intensity, which is in stark contrast to the highly probe-frequency dependent perturbed free-induction decays or uncoupled Rabi oscillations (‘flopping')59.…”

Section: Resultsmentioning

confidence: 98%

Modified relaxation dynamics and coherent energy exchange in coupled vibration-cavity polaritons

et al. 2016

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Coupling vibrational transitions to resonant optical modes creates vibrational polaritons shifted from the uncoupled molecular resonances and provides a convenient way to modify the energetics of molecular vibrations. This approach is a viable method to explore controlling chemical reactivity. In this work, we report pump–probe infrared spectroscopy of the cavity-coupled C–O stretching band of W(CO)6 and the direct measurement of the lifetime of a vibration-cavity polariton. The upper polariton relaxes 10 times more quickly than the uncoupled vibrational mode. Tuning the polariton energy changes the polariton transient spectra and relaxation times. We also observe quantum beats, so-called vacuum Rabi oscillations, between the upper and lower vibration-cavity polaritons. In addition to establishing that coupling to an optical cavity modifies the energy-transfer dynamics of the coupled molecules, this work points out the possibility of systematic and predictive modification of the excited-state kinetics of vibration-cavity polariton systems.

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Section: Resultsmentioning

confidence: 98%

Modified relaxation dynamics and coherent energy exchange in coupled vibration-cavity polaritons

et al. 2016

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“…S13). To minimize these oscillations, these data were filtered using an established method 72,73 for removing time-and frequency-dependent oscillations due to perturbed free-induction decay (PFID); 74,75 the resulting filtered transients are shown in Figs. 2 and 3.…”

Section: Results and Analysismentioning

confidence: 99%

“…The transient behavior of RDX is qualitatively similar for both pump frequencies and, except where noted, the following descriptions will apply to all transient results. To avoid the interpretation of coherent artifacts, [74][75][76] we will limit our analysis to signal occurring for Δt ≥ 0.3 ps. By 0.3 ps, the transient spectra show a negative change in absorbance due to stimulated emission or loss of ground state absorption (henceforth referred to as "bleach") from all vibrational modes across the probed spectral range.…”

Section: Frequencymentioning

confidence: 99%

Mode-Selective Vibrational Energy Transfer Dynamics in 1,3,5-Trinitroperhydro-1,3,5-Triazine (RDX) Thin Films

Cole-Filipiak¹,

Knepper²,

Wood³

et al. 2021

Preprint

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Herein, we report on the sub-picosecond to sub-nanosecond vibrational energy transfer (VET) dynamics of the solid energetic material 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) using broadband, ultrafast infrared transient absorption spectroscopy. Experiments reveal VET occurring on three distinct timescales: sub-picosecond, 5 ps, and 200 ps. The ultrafast appearance of signal at all probed modes in the mid-infrared suggests strong anharmonic coupling of all vibrations in the solid whereas the long-lived evolution demonstrates that VET is incomplete, and thus thermal equilibrium is not attained, even on the hundred picosecond timescale. Mode-selectivity of the longest dynamics suggests coupling of the N–N and axial NO<sub>2</sub> stretching modes with the long-lived, excited phonon bath.

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“…Under this framework, harmonic waves cease to be solutions of Maxwell's equations, and effects such as frequency conversion, [36][37][38] photon acceleration, 35 nonreciprocal light reflection, beam steering or focusing [39][40][41] that are impossible in stationary systems rise, similar to original works in rapidly generated plasmas. 42,43 The frequency conversion that has recently been demonstrated for metasurfaces also has origins similar to that of the coherent artifact in ultrafast time-resolved infrared (IR) spectroscopy of vibrational transitions in chemical systems 44,45 and for semiconductors, 46,47 which manifest at negative time delays, when the probe pulse precedes the pump pulse. Even though many systems have demonstrated linear frequency conversion due to abrupt time modulation, ultrafast studies of nonlinear responses, [48][49][50][51] which are prominent in resonant metasurfaces, are yet to unveil the control of light frequency for nonlinearly generated waves.…”

Section: Introductionmentioning

confidence: 93%

Externally driven nonlinear time-variant metasurfaces

Zubyuk¹,

Shafirin²,

Shcherbakov³

et al. 2020

Preprint

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Resonant photonic nanostructures exhibiting enhanced nonlinear responses and efficient frequency conversion are an emergent platform in nonlinear optics. High-index semiconductor metasurfaces with rapidly tuned high-Q resonances enable a novel class of time-variant metasurfaces, which expands the toolbox of color management at the nanoscale. Here, we report on the dynamic control of the nonlinear optical response in time-variant semiconductor metasurfaces supporting high-quality factor resonances in the near-infrared spectral range. Pump-probe measurements of germanium metasurfaces at negative pump-probe time delays reveals frequency conversion in the fundamental beam and a blue-shift of 10 nm (3.05ω) and 40% broadening in the third harmonic signal due to the photoinduced time-variant refractive index. A time-dependent coupled-mode theory, in excellent agreement with the experimental data, validated the time-variant nature of the system. Our findings expand the scope of time-variant metasurfaces and may serve as base for the next generation of nanoscale pulse shapers, optical switches and light sources.

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Perturbed free induction decay in ultrafast mid-IR pump–probe spectroscopy

Cited by 26 publications

References 20 publications

Modified relaxation dynamics and coherent energy exchange in coupled vibration-cavity polaritons

Modified relaxation dynamics and coherent energy exchange in coupled vibration-cavity polaritons

Mode-Selective Vibrational Energy Transfer Dynamics in 1,3,5-Trinitroperhydro-1,3,5-Triazine (RDX) Thin Films

Externally driven nonlinear time-variant metasurfaces

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