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Author

Marc M. Wefers

Bio: Marc M. Wefers is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Pulse shaping & Ultrashort pulse. The author has an hindex of 11, co-authored 16 publications receiving 1063 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a rigorous analysis of ultrashort pulse shaping by the spectral filtering of dispersed frequency components is presented, focusing on the case of two liquid-crystal spatial light modulators used to provide programmable manipulation of both the phase and amplitude profiles of the shaped waveform in the time domain.
Abstract: A rigorous analysis of ultrashort pulse shaping by the spectral filtering of dispersed frequency components is presented. Particular attention is directed toward the case of two liquid-crystal spatial light modulators used to provide programmable manipulation of both the phase and the amplitude profiles of the shaped waveform in the time domain. Different optical configurations are evaluated and their theoretical and practical effects determined. An important result is that, even with optimal alignment and components, the diffraction arising from spectral filtering necessarily produces a transverse spatial shift that varies linearly along the temporal profile of the shaped waveform. Despite this effect it is shown that the technique can generate arbitrary phase and amplitude temporal profiles (subject to limitations in temporal extent and temporal resolution) for the Gaussian spatial component of the shaped output waveform.

228 citations

Journal ArticleDOI
TL;DR: Two liquid-crystal spatial light modulators are employed in a novel arrangement to permit the generation of programmable ultrashort waveforms with exceptional versatility and fidelity and the time-dependent polarization profile is controlled.
Abstract: We report advances in the generation of ultrafast optical waveforms with programmable time-dependent amplitude and temporal phase profiles. Two liquid-crystal spatial light modulators are employed in a novel arrangement to permit the generation of programmable ultrashort waveforms with exceptional versatility and fidelity. We also demonstrate ultrafast waveform generation in which the time-dependent polarization profile is controlled.

184 citations

Journal ArticleDOI
TL;DR: This work reports programmable femtosecond pulseshaping using two commercially avaliable liquid crystal spatial light modulators (SLM) that allows generation of waveforms with arbitrary temporal phase and amplitude profiles within a 2.9 picosecond time window with features of less than 100 femToseconds.
Abstract: We report programmable femtosecond pulseshaping using two commercially avaliable liquid crystal spatial light modulators (SLM). This allows generation of waveforms with arbitrary temporal phase and amplitude profiles within a 2.9 picosecond time window with features of less than 100 femtoseconds. Such waveforms suggest exciting prospects for the control of chemical behaviour.

167 citations

Journal ArticleDOI
TL;DR: In this paper, the space-time profiles of ultrafast optical waveforms shaped by filtering of spatially separated frequency components are derived for single and double passes through a pulse shaping apparatus.
Abstract: A derivation of the space-time profiles of ultrafast optical waveforms shaped by filtering of spatially separated frequency components is presented. Closed form expressions for the space-time impulse response functions are given for the cases of single and double passes through a pulse shaping apparatus. For a single pass and a short unshaped pulse, diffraction by the mask filter gives rise to a translational spatial shift in the desired electric field profile that varies linearly with time along the shaped waveform. This result is completely general, and applies to frequency-domain pulse shaping with either continuous or discrete mask filters. It is also shown that double passing the apparatus does not generally reverse this effect but rather introduces further space-time coupling such as a time-varying spotsize. Examples of specific mask patterns are presented and implications for the generation of high-fidelity shaped optical waveforms are discussed.

129 citations

Journal ArticleDOI
TL;DR: A review is presented of femtosecond pulse-shaping methods and their application to spectroscopy of atoms, molecules, and condensed materials and theoretical predictions and qualitative discussions of optical control possibilities involving complex ultrafast waveforms.
Abstract: A review is presented of femtosecond pulse-shaping methods and their application to spectroscopy of atoms, molecules, and condensed materials. Pulse shaping can be used to generate femtosecond pulse sequences and other optical waveforms whose time-dependent amplitude, phase, frequency, and polarization profiles are all specified precisely. The light­matter interaction mechanisms through which such waveforms can be used for optical control over molecular and material responses are discussed. Most of the spectroscopic experiments conducted to date that involve shaped femtosecond waveforms are reviewed. These have involved control over coherent electronic responses of atoms, small molecules, and multiple quantum wells and control over coherent molecular and lattice vibrations. A selective review is presented of theoretical predictions and qualitative discussions of optical control possibilities involving complex ultrafast waveforms

119 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the field of femtosecond pulse shaping is reviewed, and applications of pulse shaping to optical communications, biomedical optical imaging, high power laser amplifiers, quantum control, and laser-electron beam interactions are reviewed.
Abstract: We review the field of femtosecond pulse shaping, in which Fourier synthesis methods are used to generate nearly arbitrarily shaped ultrafast optical wave forms according to user specification. An emphasis is placed on programmable pulse shaping methods based on the use of spatial light modulators. After outlining the fundamental principles of pulse shaping, we then present a detailed discussion of pulse shaping using several different types of spatial light modulators. Finally, new research directions in pulse shaping, and applications of pulse shaping to optical communications, biomedical optical imaging, high power laser amplifiers, quantum control, and laser-electron beam interactions are reviewed.

2,051 citations

Journal ArticleDOI
TL;DR: The last volume of the Progress in Optics series as discussed by the authors contains seven chapters on widely diverging topics, written by well-known authorities in their fields, including laser selective photophysics and photochemistry, laser phase profile generation, laser beamforming, and laser laser light emission from high-current surface spark discharges.
Abstract: Have you ever felt that the very title, Progress in Optics, conjured an image in your mind? Don’t you see a row of handsomely printed books, bearing the editorial stamp of one of the most brilliant members of the optics community, and chronicling the field of optics since the invention of the laser? If so, you are certain to move the bookend to make room for Volume 16, the latest of this series. It contains seven chapters on widely diverging topics, written by well-known authorities in their fields. These are: 1) Laser Selective Photophysics and Photochemistry by V. S. Letokhov, 2) Recent Advances in Phase Profiles (sic) Generation by J. J. Clair and C. I. Abitbol, 3 ) Computer-Generated Holograms: Techniques and Applications by W.-H. Lee, 4) Speckle Interferometry by A. E. Ennos, 5 ) Deformation Invariant, Space-Variant Optical Pattern Recognition by D. Casasent and D. Psaltis, 6) Light Emission from High-Current Surface-Spark Discharges by R. E. Beverly, and 7) Semiclassical Radiation Theory within a QuantumMechanical Framework by I. R. Senitzkt. The breadth of topic matter spanned by these chapters makes it impossible, for this reviewer at least, to pass judgement on the comprehensiveness, relevance, and completeness of every chapter. With an editorial board as prominent as that of Progress in Optics, however, it seems hardly likely that such comments should be necessary. It should certainly be possible to take the authority of each author as credible. The only remaining judgment to be made on these chapters is their readability. In short, what are they like to read? The first sentence of the first chapter greets the eye with an obvious typographical error: “The creation of coherent laser light source, that have tunable radiation, opened the . . . .” Two pages later we find: “When two types of atoms or molecules of different isotopic composition ( A and B ) have even one spectral line that does not overlap with others, it is pos-

1,071 citations

Journal ArticleDOI
TL;DR: Fundamental theoretical ideas in nanoplasmonics are reviewed and selected experimental developments are reviewed, including fundamentals, nanolocalization of optical energy and hot spots, ultrafast nanoplAsmonics and control of the spatiotemporal Nanolocalized fields.
Abstract: A review of nanoplasmonics is given. This includes fundamentals, nanolocalization of optical energy and hot spots, ultrafast nanoplasmonics and control of the spatiotemporal nanolocalization of optical fields, and quantum nanoplasmonics (spaser and gain-assisted plasmonics). This article reviews both fundamental theoretical ideas in nanoplasmonics and selected experimental developments. It is designed both for specialists in the field and general physics readership.

1,054 citations

Journal ArticleDOI
05 May 2000-Science
TL;DR: The preview of the field presented here suggests that important advances in the control of molecules and the capability of learning about molecular interactions may be reached through the application of emerging theoretical concepts and laboratory technologies.
Abstract: This review puts into perspective the present state and prospects for controlling quantum phenomena in atoms and molecules. The topics considered include the nature of physical and chemical control objectives, the development of possible quantum control rules of thumb, the theoretical design of controls and their laboratory realization, quantum learning and feedback control in the laboratory, bulk media influences, and the ability to utilize coherent quantum manipulation as a means for extracting microscopic information. The preview of the field presented here suggests that important advances in the control of molecules and the capability of learning about molecular interactions may be reached through the application of emerging theoretical concepts and laboratory technologies.

997 citations

Journal ArticleDOI
27 Apr 2001-Science
TL;DR: Strong-field control appears to have generic applicability for manipulating molecular reactivity because the tailored intense laser fields can dynamically Stark shift many excited states into resonance, and consequently, the method is not confined by resonant spectral restrictions found in the perturbative (weak-field) regime.
Abstract: We used strong-field laser pulses that were tailored with closed-loop optimal control to govern specified chemical dissociation and reactivity channels in a series of organic molecules. Selective cleavage and rearrangement of chemical bonds having dissociation energies up to approximately 100 kilocalories per mole (about 4 electron volts) are reported for polyatomic molecules, including (CH 3 ) 2 CO (acetone), CH 3 COCF 3 (trifluoroacetone), and C 6 H 5 COCH 3 (acetophenone). Control over the formation of CH 3 CO from (CH 3 ) 2 CO, CF 3 (or CH 3 ) from CH 3 COCF 3 , and C 6 H 5 CH 3 (toluene) from C 6 H 5 COCH 3 was observed with high selectivity. Strong-field control appears to have generic applicability for manipulating molecular reactivity because the tailored intense laser fields (about 10 13 watts per square centimeter) can dynamically Stark shift many excited states into resonance, and consequently, the method is not confined by resonant spectral restrictions found in the perturbative (weak-field) regime.

816 citations