Time-Resolved Reflectivity Measurements of Femtosecond-Optical-Pulse-Induced Phase Transitions in Silicon

Shank, C. V.; Yen, R.; Hirlimann, Charles

doi:10.1103/physrevlett.50.454

Cited by 544 publications

(152 citation statements)

References 9 publications

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“…For irradiation with pulses longer than several picoseconds and for near-threshold femtosecond pulses, following nucleation of the liquid phase at the surface, a thin liquid layer grows into the bulk of the material at a velocity limited by the speed of sound, but typically at a rate on the order of angstroms per picoseconds. In contrast, for fluences twice the melting threshold or greater [12][13][14][15] a significantly faster, sub-picosecond change of the linear optical properties at the surface is seen, with reflectivities reaching values equal to that of the conventional liquid phase in a few hundred femtoseconds [15]. In other experiments, a reduction in the second-harmonic-inreflection signal, suggesting a sub-picosecond loss of crystalline order at the very surface, was also seen [12,14].…”

Section: Introductionmentioning

confidence: 89%

“…In contrast, for fluences twice the melting threshold or greater [12][13][14][15] a significantly faster, sub-picosecond change of the linear optical properties at the surface is seen, with reflectivities reaching values equal to that of the conventional liquid phase in a few hundred femtoseconds [15]. In other experiments, a reduction in the second-harmonic-inreflection signal, suggesting a sub-picosecond loss of crystalline order at the very surface, was also seen [12,14]. These observations indirectly indicate that an ultrafast solid-to-liquid phase transition occurs at the surface of the semiconductor on a time-scale faster than carrier-lattice equilibration times.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Direct Observation of Ultrafast Non-thermal Melting by Ultrafast X-ray Diffraction

Siders

Cavalleri

Sokolowski‐Tinten³

et al. 2001

Ultrafast Phenomena XII

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Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Direct Observation of Ultrafast Non-thermal Melting by Ultrafast X-ray Diffraction

Siders

Cavalleri

Sokolowski‐Tinten³

et al. 2001

Ultrafast Phenomena XII

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“…Recent optical experiments provide some evidence of laser-induced disordering in crystalline silicon on a time scale comparable to the phonon period (~70 fs) [4][5][6]. Nevertheless, because optical measurements do not provide direct information about the atomic positions and coordination, they are unable to address the fundamental scientific questions related to structural dynamics in this regime.…”

Section: Time-resolved Bragg Diffraction Of Order-disorder Transitionsmentioning

confidence: 99%

Ultrafast X-ray science at the advanced light source

Schoenlein

Chin

Chong

et al. 2001

Synchrotron Radiation News

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Our scientific understanding of the static or time-averaged structure of condensed matter on the atomic scale has been dramatically advanced by direct structural measurements using x-ray techniques and modern synchrotron sources. Of course the structure of condensed matter is not static, and to understanding the behavior of condensed matter at the most fundamental level requires structural measurements on the time scale on which atoms move. The evolution of condensed-matter structure, via the making and breaking of chemical bonds and the rearrangement of atoms, occurs on the fundamental time scale of a vibrational period, ~100 fs.Atomic motion and structural dynamics on this time scale ultimately determine the course of phase transitions in solids, the kinetic pathways of chemical reactions, and even the efficiency and function of biological processes. The integration of x-ray measurement techniques, a highbrightness femtosecond x-ray source, femtosecond lasers, and stroboscopic pump-probe techniques will provide the unique capability to address fundamental scientific questions in solidstate physics, chemistry, AMO physics, and biology involving structural dynamics. In this paper, we review recent work in ultrafast x-ray science at the ALS including time-resolved diffraction measurements and efforts to develop dedicated beamlines for femtosecond x-ray experiments.Schoenlein et al. Advanced Light SourcePage 2 of 13 Time-Resolved Bragg Diffraction of Order-Disorder TransitionsInitial time-resolved x-ray experiments at the ALS have focus on order-disorder transitions in crystalline solids. The dynamics of such phase transformations are of fundamental scientific interest since they determine the genesis and evolution of new structural phases. The conventional description of simple first-order solid/liquid phase transitions in crystals is based on a thermal model, which assumes local thermal equilibrium among the vibrational modes and between the electronic and vibrational energy reservoirs. In such a model, the phase transition proceeds via energy transfer to the lattice in the form of heat. The thermal model then predicts that following optical excitation, a phase transition will evolve on the time scale determined by electron-phonon energy exchange, typically several picoseconds. Implicit in such a description is the assumption that excitation or energy deposition to the solid is slow compared to a vibrational period or to electron-phonon scattering times. However, ultrafast optical pulses can deposit energy on time scales that are short compared to electron-phonon interaction times; thereby creating electron temperatures well in excess of the underlying lattice temperature. Energy can even be deposited on time scales shorter than electron-electron scattering times (<100 fs), creating non-equilibrium (non-Fermi) electron distributions. Under such conditions, the thermal melting model breaks down, and new physical effects emerge.Ultrafast energy deposition raises fundamental scientific questions about how phase tra...

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“…To date, ultrafast non-equilibrium phase transitions in crystals with diamond and zincblende lattice structure (Si, GaAs, and InSb) have been studied using a variety of indirect optical techniques [40][41][42][43][44][45][46]. Recent optical experiments provide some evidence of laser-induced disordering in crystalline silicon on a time scale comparable to the phonon period (~70 fs) [42,44,47].…”

Section: Iv2 Order-disorder Transitions In Solids and At Surfacesmentioning

confidence: 99%

Proposal to DOE Basic Energy Sciences: Ultrafast X-ray science facility at the Advanced Light Source

Schoenlein¹,

Falcone²,

Alivisatos³

et al. 2001

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Time-Resolved Reflectivity Measurements of Femtosecond-Optical-Pulse-Induced Phase Transitions in Silicon

Cited by 544 publications

References 9 publications

Direct Observation of Ultrafast Non-thermal Melting by Ultrafast X-ray Diffraction

Direct Observation of Ultrafast Non-thermal Melting by Ultrafast X-ray Diffraction

Ultrafast X-ray science at the advanced light source

Proposal to DOE Basic Energy Sciences: Ultrafast X-ray science facility at the Advanced Light Source

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