Optimized ancillae generation for ultra-broadband two-dimensional spectral-shearing interferometry

Borrego-Varillas, Rocío; Oriana, Aurelio; Branchi, Federico; Cerullo, Giulio; Manzoni, Cristian

doi:10.1364/josab.32.001851

Cited by 27 publications

(18 citation statements)

References 19 publications

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“…Type II sum frequency generation of this 6 fs pulse with the fundamental 800 nm pulse generates the 45-nm broad pulse centered at 400 nm and used for resonant excitation. The FWHM duration of the latter blue pulse is measured to be 8.5 fs by implementing 2D spectral shearing interferometry (2DSI) 38 , 39 . Before TA experiments, the duration of either pump pulse is optimized directly in the sample by fine tuning group velocity dispersion with a pair of fused silica wedges (in combination with the chirped mirrors) so as to generate a white light supercontinuum in the solvent (methanol) with minimum pump intensity.…”

Section: Methodsmentioning

confidence: 99%

Engineering the vibrational coherence of vision into a synthetic molecular device

Gueye¹,

Manathunga²,

Agathangelou³

et al. 2018

Nat Commun

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The light-induced double-bond isomerization of the visual pigment rhodopsin operates a molecular-level optomechanical energy transduction, which triggers a crucial protein structure change. In fact, rhodopsin isomerization occurs according to a unique, ultrafast mechanism that preserves mode-specific vibrational coherence all the way from the reactant excited state to the primary photoproduct ground state. The engineering of such an energy-funnelling function in synthetic compounds would pave the way towards biomimetic molecular machines capable of achieving optimum light-to-mechanical energy conversion. Here we use resonance and off-resonance vibrational coherence spectroscopy to demonstrate that a rhodopsin-like isomerization operates in a biomimetic molecular switch in solution. Furthermore, by using quantum chemical simulations, we show why the observed coherent nuclear motion critically depends on minor chemical modifications capable to induce specific geometric and electronic effects. This finding provides a strategy for engineering vibrationally coherent motions in other synthetic systems.

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Section: Methodsmentioning

confidence: 99%

Engineering the vibrational coherence of vision into a synthetic molecular device

Gueye¹,

Manathunga²,

Agathangelou³

et al. 2018

Nat Commun

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“…The pump pulses are temporally compressed by 2 chirped mirrors in the visible and by a MgF 2 prism compressor in the UV [73]. The pulse characterization is performed by frequency-resolved optical gating in the visible, and by a two-dimensional spectral-shearing interferometry method (2DSI) in the UV [74]. For all pump photon energies, the temporal duration is<20fs.…”

Section: Ultrafast Pump-probe Spectroscopymentioning

confidence: 99%

Strongly Coupled Coherent Phonons in Single-Layer MoS₂

et al. 2020

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We present a transient absorption setup combining broadband detection over the visible-UV range with high temporal resolution (∼20fs) which is ideally suited to trigger and detect vibrational coherences in different classes of materials. We generate and detect coherent phonons (CPs) in single layer (1L) MoS2, as a representative semiconducting 1L-transition metal dichalcogenide (TMD), where the confined dynamical interaction between excitons and phonons is unexplored. The coherent oscillatory motion of the out-of-plane A ′ 1 phonons, triggered by the ultrashort laser pulses, dynamically modulates the excitonic resonances on a timescale of few tens fs. We observe an enhancement by almost two orders of magnitude of the CP amplitude when detected in resonance with the C exciton peak, combined with a resonant enhancement of CP generation efficiency. Ab initio calculations of the change in 1L-MoS2 band structure induced by the A ′ 1 phonon displacement confirm a strong coupling with the C exciton. The resonant behavior of the CP amplitude follows the same spectral profile of the calculated Raman susceptibility tensor. This demonstrates that CP excitation in 1L-MoS2 can be described as a Raman-like scattering process. These results explain the CP generation process in 1L-TMDs, paving the way for coherent all-optical control of excitons in layered materials in the THz frequency range.Coherent modulation of the optical properties of a material, following impulsive photo-excitation of the lattice, is fundamentally interesting and technologically relevant because it can be used for applications in sensors[1], actuators and transducers [2][3][4], that can be operated at extremely high frequencies (up to several THz[5]). In order to exploit this effect, it is necessary to understand the mechanism underlying the coherent phonon (CP) generation process and to identify the physical parameters (such as the pump pulse photon energy) that allow their efficient excitation. In view of possible device applications, it is of paramount importance to detect the spectral dependence of the CP amplitude, in order to identify in which photon energy window the optical response of the material can be efficiently modulated.We present a novel transient absorption (TA) setup, combining broadband detection from 1.8 to 3eV, with extremely high temporal resolution (∼20fs). This is ideally suited to trigger and detect vibrational coherences in different classes of materials. We use it to generate and detect CPs in 1L-MoS 2 , as a representative semiconducting 1L-transition metal dichalcogenide (TMD). We focus on TMDs because they support strongly bound excitons with unique physical properties, enabling novel applica-tions in optoelectronics and photonics [6][7][8]. However, in TMDs, the dynamical interaction between excitons and phonons, when constrained to 1L, is unexplored.When TMDs are exfoliated down to 1L, they undergo a transition from indirect to direct band gap[9], accompanied by a strong enhancement of the photoluminescence (PL) quantum yie...

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“…In TA spectroscopy with WLC probe and broadband detection, the time resolution is determined essentially by the duration of the pump pulse [11]; for this reason, it is crucial to precisely characterize its temporal profile. For this purpose, we adopt a modified scheme of two-dimensional spectral shearing interferometry (2DSI), recently developed by some of the authors [75], which is suitable for the full characterization of UV pulses. The 2DSI method [76,77] relies on spectral shearing interferometry with zero delay; with respect to the SPIDER technique, which encodes phase as a sensitively calibrated fringe in the spectral domain, 2DSI robustly encodes phase along a second dimension.…”

Section: Uv Pulse Characterizationmentioning

confidence: 99%

Ultraviolet Transient Absorption Spectrometer with Sub-20-fs Time Resolution

et al. 2018

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We describe a transient absorption (TA) spectroscopy system in the ultraviolet (UV) spectral range, for the study of the ultrafast optical response of biomolecules. After reviewing the techniques for the generation and characterization of ultrashort UV pulses, we describe the experimental setup of our ultrabroadband UV TA spectrometer. The setup combines sub-20-fs UV pump pulses tunable between 3.35 and 4.7 eV, with broadband white-light-continuum probe pulses in the 1.7-4.6 eV range. Thanks to the broad tunability of the pump pulses in the UV spectral range, the extremely high temporal resolution and the broad spectral coverage of the probe, this TA system is a powerful and versatile tool for the study of many biomolecules. As an example of its potential, we apply the TA spectrometer to track ultrafast internal conversion processes in pyrene after excitation in the UV, and to resolve an impulsively excited molecular vibration with 85-fs period.

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Optimized ancillae generation for ultra-broadband two-dimensional spectral-shearing interferometry

Cited by 27 publications

References 19 publications

Engineering the vibrational coherence of vision into a synthetic molecular device

Engineering the vibrational coherence of vision into a synthetic molecular device

Strongly Coupled Coherent Phonons in Single-Layer MoS₂

Ultraviolet Transient Absorption Spectrometer with Sub-20-fs Time Resolution

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Optimized ancillae generation for ultra-broadband two-dimensional spectral-shearing interferometry

Cited by 27 publications

References 19 publications

Engineering the vibrational coherence of vision into a synthetic molecular device

Engineering the vibrational coherence of vision into a synthetic molecular device

Strongly Coupled Coherent Phonons in Single-Layer MoS2

Ultraviolet Transient Absorption Spectrometer with Sub-20-fs Time Resolution

Contact Info

Product

Resources

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Strongly Coupled Coherent Phonons in Single-Layer MoS₂