Femtosecond ≈ FemtosecondFemtosecond
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Colloidal CsPbX<sub>3</sub> (X = Cl, Br, I) Nanocrystals 2.0: Zwitterionic Capping Ligands for Improved Durability and Stability Open
Colloidal lead halide perovskite nanocrystals (NCs) have recently emerged as versatile photonic sources. Their processing and optoelectronic applications are hampered by the loss of colloidal stability and structural integrity due to the f…
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Sub-Micron Polymeric Stomatocytes as Promising Templates for Confined Crystallization and Diffraction Experiments Open
The possibility of using sub-micrometer polymeric stomatocytes is investigated to effectuate confined crystallization of inorganic compounds. These bowl-shaped polymeric compartments facilitate confined crystallization while their glassy s…
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Linac Coherent Light Source: The first five years Open
A new scientific frontier opened in 2009 with the start of operations of the world's first x-ray free-electron laser (FEL), the Linac Coherent Light Source (LCLS), at SLAC National Accelerator Laboratory. LCLS provides femtosecond pulses o…
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Advances in attosecond science Open
Attosecond science offers formidable tools for the investigation of electronic processes at the heart of important physical processes in atomic, molecular and solid-state physics. In the last 15 years impressive advances have been obtained…
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Femtosecond structural dynamics drives the trans/cis isomerization in photoactive yellow protein Open
Visualizing a response to light Many biological processes depend on detecting and responding to light. The response is often mediated by a structural change in a protein that begins when absorption of a photon causes isomerization of a chr…
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Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam Open
We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementation of the instrument, the photoemitter concept and the qu…
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Retinal isomerization in bacteriorhodopsin captured by a femtosecond x-ray laser Open
Look fast Organisms from bacteria to humans sense and react to light. Proteins that contain the light-sensitive molecule retinal couple absorption of light to conformational changes that produce a signal or move ions across a membrane. Nog…
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Time-resolved x-ray absorption spectroscopy with a water window high-harmonic source Open
An x-ray view of C–F and S–F bond breaks X-ray absorption spectroscopy is a useful probe of element-specific dynamics in molecular reactions. However, the required x-ray fluxes have rarely been available outside expensive dedicated facilit…
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Resolving the build-up of femtosecond mode-locking with single-shot spectroscopy at 90 MHz frame rate Open
Mode-locked lasers have enabled some of the most precise measurements ever performed, from attosecond time-domain spectroscopy to metrology with frequency combs. However, such extreme precision belies the complexity of the underlying mode-…
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Preparation of Monolayer MoS2 Quantum Dots using Temporally Shaped Femtosecond Laser Ablation of Bulk MoS2 Targets in Water Open
Zero-dimensional MoS 2 quantum dots (QDs) possess distinct physical and chemical properties, which have garnered them considerable attention and facilitates their use in a broad range of applications. In this study, we prepared monolayer M…
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External field-assisted laser ablation in liquid: An efficient strategy for nanocrystal synthesis and nanostructure assembly Open
Laser ablation in liquid (LAL) has received considerable attention over the last decade, and is gradually becoming an irreplaceable technique to synthesize nanocrystals and fabricate functional nanostructures because it can offer effective…
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Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres Open
Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so tha…
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Femtosecond x-ray spectroscopy of an electrocyclic ring-opening reaction Open
X-ray vision catches Woodward-Hoffmann The celebrated Woodward-Hoffmann (W-H) rules rationalize a variety of rapid bond rearrangements in organic molecules. The key insight involved symmetry conservation in the electronic journey from reac…
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Roadmap of ultrafast x-ray atomic and molecular physics Open
X-ray free-electron lasers (XFELs) and table-top sources of x-rays based upon high harmonic generation (HHG) have revolutionized the field of ultrafast x-ray atomic and molecular physics, largely due to an explosive growth in capabilities …
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Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer Open
Significance We have revisited the 2D spectroscopy of the excitation energy transfer in the Fenna–Matthews–Olson (FMO) protein. Based on 2D spectroscopic signatures, the energy transfer dynamics in the FMO protein has been argued to be sup…
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Interlayer Coupling in Twisted WSe<sub>2</sub>/WS<sub>2</sub> Bilayer Heterostructures Revealed by Optical Spectroscopy Open
van der Waals (vdW) heterostructures are promising building blocks for future ultrathin electronics. Fabricating vdW heterostructures by stamping monolayers at arbitrary angles provides an additional range of flexibility to tailor the resu…
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All polarization-maintaining fiber laser architecture for robust femtosecond pulse generation Open
We report on a novel architecture for robust mode-locked femtosecond fiber lasers using a nonlinear optical loop mirror with all polarization-maintaining fibers. Due to a nonreciprocal phase shift, the loop mirror can be operated in a comp…
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Three-dimensional chiral microstructures fabricated by structured optical vortices in isotropic material Open
Optical vortices, a type of structured beam with helical phase wavefronts and 'doughnut'-shaped intensity distributions, have been used to fabricate chiral structures in metals and spiral patterns in anisotropic polarization-dependent azob…
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Crossover from hydrogen to chemical bonding Open
The nature of short hydrogen bonds Hydrogen bonding (H-bonding) unquestionably plays an important role in chemical and biological systems and is responsible for some of their unusual properties. Strong, short H-bonds constitute a separate …
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Erbium-doped chalcogenide glass thin film on silicon using femtosecond pulsed laser with different deposition temperatures Open
The properties of Er3+- doped gallium lanthanum sulphide thin films prepared on a silicon substrate by femtosecond pulsed laser deposition were studied as a function of process temperature. The films were characterised using transition ele…
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Raman Self-Frequency Shift of Dissipative Kerr Solitons in an Optical Microresonator Open
The formation of temporal dissipative Kerr solitons in microresonators driven by a continuous-wave laser enables the generation of coherent, broadband, and spectrally smooth optical frequency combs as well as femtosecond pulse sources with…
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Applications of Few-Layer Nb<sub>2</sub>C MXene: Narrow-Band Photodetectors and Femtosecond Mode-Locked Fiber Lasers Open
Although the physicochemical properties of niobium carbide (Nb2C) have been widely investigated, their exploration in the field of photoelectronics is still at the infancy stage with many potential applications that remain to be exploited.…
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Real-Time Observation of Exciton–Phonon Coupling Dynamics in Self-Assembled Hybrid Perovskite Quantum Wells Open
Self-assembled hybrid perovskite quantum wells have attracted attention due to their tunable emission properties, ease of fabrication and device integration. However, the dynamics of excitons in these materials, especially how they couple …
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Experimental observation of the liquid-liquid transition in bulk supercooled water under pressure Open
Liquid-liquid transitions under pressure Theoretical simulations suggest that deeply supercooled water undergoes a transition between high- and low-density forms, but this transition is difficult to study experimentally because it occurs u…
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Ultrafast disordering of vanadium dimers in photoexcited VO <sub>2</sub> Open
Snapshots of a phase transition Time-resolved x-ray scattering can be used to investigate the dynamics of materials during the switch from one structural phase to another. So far, methods provide an ensemble average and may miss crucial as…
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Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser Open
A deeper look into iron selenide In the past 10 years, iron-based superconductors have created more puzzles than they have helped resolve. Some of the most fundamental outstanding questions are how strong the interactions are and what the …
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Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response Open
Carbon dots (CDs) are an emerging family of nanosystems displaying a range of fascinating properties. Broadly speaking, they can be described as small, surface-functionalized carbonaceous nanoparticles characterized by an intense and tunab…
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Reshaping, Fragmentation, and Assembly of Gold Nanoparticles Assisted by Pulse Lasers Open
The vast majority of the outstanding applications of metal nanoparticles (NPs) developed during the last two decades have arisen from their unique optical properties. Within this context, rational synthesis and assembly of gold NPs have be…
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Photoinduced Structural Dynamics of Molecular Systems Mapped by Time-Resolved X-ray Methods Open
We review the tremendous advances in ultrafast X-ray science, over the past 15 years, making the best use of new ultrashort X-ray sources including table-top or large-scale facilities. Different complementary X-ray-based techniques, includ…
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Progress in ultrafast laser processing and future prospects Open
The unique characteristics of ultrafast lasers have rapidly revolutionized materials processing after their first demonstration in 1987. The ultrashort pulse width of the laser suppresses heat diffusion to the surroundings of the processed…