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Showing papers on "Femtosecond published in 1983"


Journal ArticleDOI
TL;DR: In this article, the reflectivity of silicon has been measured following excitation with intense 90-fsec optical pulses, which can clearly resolve in time the process of energy transfer to the crystal lattice and the dynamics of the phase transition to the melted state.
Abstract: The reflectivity of silicon has been measured following excitation with intense 90-fsec optical pulses. These measurements for the first time clearly resolve in time the process of energy transfer to the crystal lattice and the dynamics of the phase transition to the melted state.

476 citations


Journal ArticleDOI
Richard L. Fork1, C. V. Shank1, Charles Hirlimann1, R. Yen1, Walter J. Tomlinson1 
TL;DR: Gigawatt white-light continuum pulses that permit spectroscopic measurements with a time resolution of 80 fsec are obtained that are consistent with self-phase modulation having a prominent role in generation of the continuum.
Abstract: We obtain gigawatt white-light continuum pulses that permit spectroscopic measurements with a time resolution of 80 fsec. These pulses extend continuously from 0.19 to 1.6 μm and have time sweeps as small as 10 fsec/1000 A. We find temporal, spatial, and spectral properties that are consistent with self-phase modulation having a prominent role in generation of the continuum.

379 citations


Journal ArticleDOI
TL;DR: In this article, the dynamics of the structural changes that take place on a silicon surface following excitation with an intense optical pulse are observed with 90-fs time resolution, and the threefold rotational symmetry of the silicon surface becomes rotationally isotropic within a picosecond after excitation consistent with a transition from the crystalline to the liquid molten state.
Abstract: The dynamics of the structural changes that take place on a silicon surface following excitation with an intense optical pulse are observed with 90-fs time resolution. The threefold rotational symmetry of the silicon $〈111〉$ surface becomes rotationally isotropic within a picosecond after excitation consistent with a transition from the crystalline to the liquid molten state.

283 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe use of colliding pulse mode locking to generate pulses of 65 fs duration and pulse compression to reduce those pulse durations to 30 fs, and amplify femtosecond pulses to gigawatt powers.
Abstract: Recent advances in generation, amplification, compression, and frequency broadening of femtosecond optical pulses are reviewed. We describe use of colliding pulse mode locking to generate pulses of 65 fs duration and pulse compression to reduce those pulse durations to 30 fs. Amplification of femtosecond pulses to gigawatt powers and frequency broadening to obtain white light continuum pulses while retaining femtosecond pulse durations are also examined.

102 citations


Journal ArticleDOI
Charles V. Shank1
04 Mar 1983-Science
TL;DR: The methods and techniques for extending time-resolved measurements into the femtosecond (10–15 second) time domain are described, and recent applications and fertile areas for investigation with femTosecond pulses are discussed.
Abstract: Considerable progress has taken place in the generation and application of ultrashort optical pulses. The methods and techniques for extending time-resolved measurements into the femtosecond (10(-15) second) time domain are described, and recent applications and fertile areas for investigation with femtosecond pulses are discussed.

72 citations



Journal ArticleDOI
TL;DR: In this paper, a three-laser tunable-induced grating technique was used for ground-state recovery of malachite green in water, and the authors observed a recovery consistent with either the sum of two decaying exponentials (0.78±0.10 and 7.4±3.0 ps) or with a uniform range of exponential values ( 0.34± 0.04 to 7.2±3 ps).
Abstract: We report measurements of the ground‐state‐recovery dynamics of malachite green in water, made using a new three‐laser tunable‐induced‐grating technique. We observe a recovery consistent with either the sum of two decaying exponentials (0.78±0.10 and 7.4±3.0 ps) or with a uniform range of exponentials (0.34±0.04 to 7.2±3.0 ps). Our three‐frequency induced‐grating method provides a new and useful approach for studying picosecond and femtosecond atomic and molecular processes, working in the frequency rather than the time domain.

39 citations



Journal ArticleDOI
TL;DR: In this article, a new technique for measuring extremely fast excited state relaxation times, on the order of or less than the laser pulse width, in the presence of a longer relaxation time is described.
Abstract: A new technique for measuring extremely fast excited state relaxation times, on the order of or less than the laser pulse width, in the presence of a longer relaxation time is described. The difficulties involved in using the conventional pump‐and‐probe technique and the corresponding advantages of the new technique are illustrated with numerical examples for specific three‐level systems. Qualitative experimental results on semiconductors and organic dye molecules substantiating the results are shown.

35 citations


Journal ArticleDOI
TL;DR: In this paper, it was demonstrated experimentally and theoretically that a cw dye laser with a ring cavity resonator and a passive mode locking can emit pulses of variable duration ranging from 1 psec down to 55 fsec and wavelengths from 615 to 624 nm.
Abstract: It is demonstrated experimentally and theoretically that a cw dye laser with a ring cavity resonator and a passive mode locking can emit pulses of variable duration ranging from 1 psec down to 55 fsec and wavelengths from 615 to 624 nm. The tuning of the pulse duration is achieved by varying the optical path in an intracavity glass prism. Phase modulation because of saturation of a nonlinear absorber compresses the pulses in the dispersive material of the prism. A theoretical model of mode self-locking between colliding pulses is proposed.

25 citations


Journal ArticleDOI
TL;DR: The transient behavior of parametric-scattering four-wave mixing is investigated experimentally with femtosecond laser pulses, yielding high-power pulses of less than 40-fsec duration.
Abstract: The transient behavior of parametric-scattering four-wave mixing is investigated experimentally with femtosecond laser pulses. Special emphasis is placed on the measurement of parametric pulse durations and the application of this process to the compression of femtosecond optical pulses. Compression factors up to 1.85 have been achieved, yielding high-power pulses of less than 40-fsec duration.

Journal ArticleDOI
TL;DR: Transient stimulated Raman scattering of amplified pulses from a passively mode-locked ring cw dye laser has been demonstrated to be a useful method for the production of coherent near infrared femtosecond light pulses as mentioned in this paper.
Abstract: Transient stimulated Raman scattering of amplified pulses from a passively mode‐locked ring cw dye laser has been demonstrated to be a useful method for the production of coherent near infrared femtosecond light pulses. Hypershort Stokes radiation is generated in capillary waveguides containing high pressure hydrogen (830 nm, 1265 nm) and methane (752 nm, 964 nm, 1340 nm) and pulse shortening factors as large as 2.9 have been observed.

Journal ArticleDOI
TL;DR: In this paper, a femtosecond optical Kerr shutter was used with β-carotene in acetone solution, achieving a resolution better than 1 ps with a dynamic range of 100.
Abstract: Conjugated molecules, with large optical nonlinearities, are tested as materials usable for femtosecond optical Kerr shutter technique. With β‐carotene, in acetone solution, we have achieved responses limited by the 100‐fs width of the optical pulses and characterized by a resolution better than 1 ps with a dynamic range of 100.

Journal ArticleDOI
TL;DR: In this article, the authors describe the dynamics of structural changes that take place on a silicon surface following excitation with an intense optical pulse, and show that the three-fold rotational symmetry of the silicon surface becomes rotationally isotropic within a picosecond after excitation consistent with a transition from the crystalline to the liquid molten state.
Abstract: Laser processing of materials has raised a number of interesting issues relating to phase transitions and the structure of optically excited semiconductors. In this paper we describe the dynamics of structural changes that take place on a silicon surface following excitation with an intense optical pulse. Second harmonic generation from the silicon surface is used as a tool to measure crystalline order with 90 femtosecond resolution. The three-fold rotational symmetry of the silicon surface is observed to become rotationally isotropic within a picosecond after excitation consistent with a transition from the crystalline to the liquid molten state.

Proceedings ArticleDOI
01 Mar 1983
TL;DR: In this paper, the Photochron IV femtosecond streak image tube is described and a more compact miniaturised version of the tube is also described and results from a preliminary theoretical evaluation of its performance are discussed.
Abstract: Some design features and performance characteristics of a Photochron IV femtosecond streak image tube are presented. A more compact miniaturised version of the tube is also described and results from a preliminary theoretical evaluation of its performance are discussed.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Journal ArticleDOI
TL;DR: In this article, the authors considered an optical resonator excited by an external light beam, where the resonator is filled with a dispersive (condensed) medium for a length of the medium close to several "tunnel" lengths.
Abstract: Stimulated Raman radiation is considered in an optical resonator excited by an external light beam. It is assumed that the resonator is filled with a dispersive (condensed) medium for a length of the medium (along the resonator axis) close to several ‘tunnel’ lengths. A Raman-active medium is assumed to fill part of the resonator length along the resonator axis. Numerical calculations are presented of tunnel locking stimulated Raman radiation components. The shape of light pulses is calculated, and the band of locking Stokes components is derived. The feasibility of generating a light pulse of duration 3 × 10-14 −4 × 10-15 s in a frequency region close to the point ∂2 n eff / ∂ω2 = 0, located usually in the infrared spectral region (n eff is the effective refractive index of the substance inside the resonator) is discussed. Also discussed is the feasibility of correcting the refractive index dispersion and generating femtosecond light pulses in the visible spectral region.


Proceedings ArticleDOI
R. Yen1, C. V. Shank1, R. L. Fork1
28 Nov 1983
TL;DR: In this article, a femtosecond optical technology was described for the generation and measurement of optical pulses as short as 30 fs using self-phase modulation of the 90 fs laser pulse in a short 15 cm optical fiber followed by grating compressor.
Abstract: In this discussion, we report two recent advances in femtosecond optical technology. Firstly, the generation and measurement of optical pulses as short as 30 fs is described. The pulses are produced using self-phase modulation of the 90 fs laser pulse in a short 15 cm optical fiber followed by a grating compressor. Finally, we report the operation of an optically synchronized streak camera which operates at 10 Hz repetition rate and has a system jitter of less than one picosecond. Synch-ronization is achieved with a Fe:InP photoconductive switch which allows for room temperature dc biasing.

Journal ArticleDOI
TL;DR: In this paper, time resolved reflectivity measurements at various wavelength are presented and interpreted in the forme of very simple models for optical pulse generation techniques pushing optical pulse widths down into the femtosecond domain.
Abstract: Recent advances have taken place in optical pulse generation techniques pushing optical pulse widths down into the femtosecond domain. Time resolved reflectivity measurements at various wavelength are presented and interpreted in the forme of very simple models.