Multiphoton intrapulse interference. IV. Ultrashort laser pulse spectral phase characterization and compensation.
TL;DR: A noninterferometric single beam method to characterize and compensate the spectral phase of ultrashort femtosecond pulses accurately and is ideally suited for the generation of tailored spectral phase functions required for coherent control experiments.
Abstract: We introduce a noninterferometric single beam method to characterize and compensate the spectral phase of ultrashort femtosecond pulses accurately. The method uses a pulse shaper that scans calibrated phase functions to determine the unknown spectral phase of a pulse. The pulse shaper can then be used to synthesize arbitrary phase femtosecond pulses or it can introduce a compensating spectral phase to obtain transform-limited pulses. This method is ideally suited for the generation of tailored spectral phase functions required for coherent control experiments.
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TL;DR: An overview of the state of the art in the field can be found in this paper, where the authors discuss present challenges and the future outlook of high-power fiber laser applications.
Abstract: High-power fibre lasers are in demand for industrial, defence and scientific applications. This review provides an overview of the present state of the art in the field and discusses present challenges and the future outlook.
781 citations
TL;DR: In this paper, a tutorial on the field of femtosecond pulse shaping, a technology that enables generation of nearly arbitrary, user defined, ultrafast optical waveforms, with control of phase, amplitude, and polari-zation, is presented.
579 citations
TL;DR: This review presents a summary of some of the most salient contributions to the field of coherent laser control from an experimentalist's perspective and highlights the fact thatSome of the highest resolution spectroscopic measurements being carried out employ femtosecond laser pulses.
Abstract: The observation of coherent dynamics ensuing from the excitation of molecular systems by femtosecond laser pulses is at the heart of femtochemistry. The time-dependent evolution of coherent superpositions of quantum states, the physical basis for the observation of coherent dynamics and their manipulation are of central importance to coherent control of physicochemical processes. In the early days of femtochemistry, there was significant skepticism regarding the type of information that could be learned from spectroscopic experiments using very short pulses. There were arguments that one could infer the dynamics from frequency-resolved experiments and that the femtosecond experiments did not offer new information. It was also assumed that experiments with very short pulses would smear the available spectroscopic information because of their broad bandwidths. Approximately two decades after the initial experiments, it has become clear that femtosecond experiments have opened an extremely valuable window into the dynamic behavior of atomic and molecular systems that is influencing how we think about physics, chemistry, and biology. In particular, we highlight the fact that some of the highest resolution spectroscopic measurements being carried out employ femtosecond laser pulses. These experiments, specifically those taking advantage of rotational coherence, provide resolution that rivals microwave spectroscopy. The reason spectroscopic information is not lost in femtochemistry experiments is coherence, a property that can be manipulated to control physicochemical processes by a number of different approaches, which will be reviewed here. This review presents a summary of some of the most salient contributions to the field of coherent laser control from an experimentalist’s perspective. While a number of theoretical papers have made key contributions to the field, it is from the experimental successes, as well as failures, that we can best learn how to implement new strategies and develop future applications. Coherent laser control, in the context of this review, encompasses experiments in which the coherent properties of the laser and/or the molecule are required for controlling a particular physicochemical process. We distinguish for each of the experiments between coherence in the laser field(s), * To whom correspondence should be addressed. Phone (517) 3559715 (ext-315). Fax (517) 353-1793. E-mail dantus@msu.edu. 1813 Chem. Rev. 2004, 104, 1813−1859
338 citations
TL;DR: The progress in controlling quantum dynamical processes in the condensed phase with femtosecond laser pulses is reviewed and adaptive femTosecond quantum control is realized, in which the optimal solution is iteratively obtained through the combination of an experimental feedback signal and an automated learning algorithm.
Abstract: We review the progress in controlling quantum dynamical processes in the condensed phase with femtosecond laser pulses. Due to its high particle density the condensed phase has both high relevance and appeal for chemical synthesis. Thus, in recent years different methods have been developed to manipulate the dynamics of condensed-phase systems by changing one or multiple laser pulse parameters. Single-parameter control is often achieved by variation of the excitation pulse’s wavelength, its linear chirp or its temporal subpulse separation in case of pulse sequences. Multiparameter control schemes are more flexible and provide a much larger parameter space for an optimal solution. This is realized in adaptive femtosecond quantum control, in which the optimal solution is iteratively obtained through the combination of an experimental feedback signal and an automated learning algorithm. Several experiments are presented that illustrate the different control concepts and highlight their broad applicability. These fascinating achievements show the continuous progress on the way towards the control of complex quantum reactions in the condensed phase.
294 citations
TL;DR: In this article, a femtosecond pulse characterization and compensation using multiphoton intrapulse interference phase scan (MIIPS) was rigorously tested and was found to have 3 mrad precision within the 90 nm bandwidth of the pulses.
Abstract: Femtosecond pulse characterization and compensation using multiphoton intrapulse interference phase scan (MIIPS) [Opt. Lett.29, 775 (2004)] was rigorously tested. MIIPS was found to have 3 mrad precision within the 90 nm bandwidth of the pulses. Group-velocity dispersion measurements of glass and quartz provided independent accuracy tests. Phase distortions from high-numerical-aperture objectives were measured and corrected using MIIPS, an important requirement for reproducible two-photon microscopy. Phase compensation greatly improved the pulse-shaping results through a more accurate delivery of continuous and binary phase functions to the sample. MIIPS measurements were possible through the scattering of biological tissue, a consideration for biomedical imaging.
283 citations
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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
TL;DR: Tailored femtosecond laser pulses from a computer-controlled pulse shaper were used to optimize the branching ratios of different organometallic photodissociation reaction channels, showing that two different bond-cleaving reactions can be selected, resulting in chemically different products.
Abstract: Tailored femtosecond laser pulses from a computer-controlled pulse shaper were used to optimize the branching ratios of different organometallic photodissociation reaction channels. The optimization procedure is based on the feedback from reaction product quantities in a learning evolutionary algorithm that iteratively improves the phase of the applied femtosecond laser pulse. In the case of CpFe(CO)2Cl, it is shown that two different bond-cleaving reactions can be selected, resulting in chemically different products. At least in this case, the method works automatically and finds optimal solutions without previous knowledge of the molecular system and the experimental environment.
1,463 citations
TL;DR: In this article, the authors summarize the problem of measuring an ultrashort laser pulse and describe in detail a technique that completely characterizes a pulse in time: frequency-resolved optical gating.
Abstract: We summarize the problem of measuring an ultrashort laser pulse and describe in detail a technique that completely characterizes a pulse in time: frequency-resolved optical gating. Emphasis is placed on the choice of experimental beam geometry and the implementation of the iterative phase-retrieval algorithm that together yield an accurate measurement of the pulse time-dependent intensity and phase over a wide range of circumstances. We compare several commonly used beam geometries, displaying sample traces for each and showing where each is appropriate, and we give a detailed description of the pulse-retrieval algorithm for each of these cases.
1,447 citations
TL;DR: In this paper, a self-referencing interferometric technique for measuring the amplitude and phase of ultrashort optical pulses is presented, which uses a collinear geometry that requires no moving components.
Abstract: We present a novel, self-referencing interferometric technique for measuring the amplitude and the phase of ultrashort optical pulses The apparatus uses a collinear geometry that requires no moving components The phase-retrieval procedure is noniterative and rapid and uses only two one-dimensional Fourier transforms We apply the technique to characterize ultrashort pulses from a mode-locked Ti:sapphire oscillator
1,183 citations
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