Pulse-shape-dependent strong-field ionization viewed with velocity-map imaging

Geißler, Dominik; Rozgonyi, Tamás; González‐Vázquez, Jesús; González, Leticia; Marquetand, Philipp; Weinacht, Thomas

doi:10.1103/physreva.84.053422

Cited by 17 publications

(26 citation statements)

References 32 publications

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“…The equilibrium geometry of CH 2 BrCl in its ground electronic state is taken from (Rozgonyi &González 2001). The excitation energies for the five lowest excited electronic states of CH 2 BrCl + were determined at the same level of theory as those for the other species (Geißler et al 2011), i,e, using the multireference configuration interaction (MRCI) method implemented in the Molpro program package (Werner et al 2012). The MRCI calculations were based on previous state-averaged complete active space self-consistent field (Roos et al 1980) computations.…”

Section: Calculationsmentioning

confidence: 99%

Strong field molecular ionization to multiple ionic states: direct versus indirect pathways

Sándor

Zhao

Rozgonyi

et al. 2014

J. Phys. B: At. Mol. Opt. Phys.

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Abstract. We present velocity map imaging measurements of photoelectrons in coincidence with ions produced via strong field molecular ionization. Our measurements, in conjunction with electronic structure and Stark shift calculations, allow us to assign several features in the low energy portion of the photoelectron spectrum to different molecular electronic continua (ionic states). Furthermore, we are able to distinguish between direct and indirect ionization pathways, uncovering the role of both neutral and ionic resonances in the ionization dynamics.

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Section: Calculationsmentioning

confidence: 99%

Strong field molecular ionization to multiple ionic states: direct versus indirect pathways

Sándor

Zhao

Rozgonyi

et al. 2014

J. Phys. B: At. Mol. Opt. Phys.

Self Cite

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“…Although past work has combined strong field pulse shaping with imaging [23][24][25] , and a few previous efforts [26][27][28][29] used VMI for adaptive control, they were exclusively based on raw images, in which the 3D momentum distributions were projected onto the two-dimensional (2D) detector plane. The azimuthal ambiguity inherent in such raw, 2D images complicated the extraction of a robust feedback signal 26 .…”

Section: Experimentmentioning

confidence: 99%

Adaptive strong-field control of chemical dynamics guided by three-dimensional momentum imaging

et al. 2013

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Shaping ultrafast laser pulses using adaptive feedback can manipulate dynamics in molecular systems, but extracting information from the optimized pulse remains difficult. Experimental time constraints often limit feedback to a single observable, complicating efforts to decipher the underlying mechanisms and parameterize the search process. Here we show, using two strong-field examples, that by rapidly inverting velocity map images of ions to recover the three-dimensional photofragment momentum distribution and incorporating that feedback into the control loop, the specificity of the control objective is markedly increased. First, the complex angular distribution of fragment ions from the no þis controlled via a barrier-suppression mechanism, a result that is validated by model calculations. Collectively, these experiments comprise a significant advance towards the fundamental goal of actively guiding population to a specified quantum state of a molecule.

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“…Thus, VMI provides angle-resolved kinetic energy release data for a given ion species at a rapid enough pace to be a candidate for use as closed-loop feedback. In fact, imaging studies of pulse-shape-dependent strong-field processes have appeared, [18][19][20][21] and some initial image-based feedback techniques have already been used by various groups. [21][22][23][24] In these initial efforts, the raw two-dimensional (2D) image was used as feedback.…”

Section: Introductionmentioning

confidence: 99%

Incorporating real time velocity map image reconstruction into closed-loop coherent control

Rallis

Burwitz

Andrews

et al. 2014

Review of Scientific Instruments

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We report techniques developed to utilize three-dimensional momentum information as feedback in adaptive femtosecond control of molecular dynamics. Velocity map imaging is used to obtain the three-dimensional momentum map of the dissociating ions following interaction with a shaped intense ultrafast laser pulse. In order to recover robust feedback information, however, the twodimensional momentum projection from the detector must be inverted to reconstruct the full threedimensional momentum of the photofragments. These methods are typically slow or require manual inputs and are therefore accomplished offline after the images have been obtained. Using an algorithm based upon an "onion-peeling" (also known as "back projection") method, we are able to invert 1040 × 1054 pixel images in under 1 s. This rapid inversion allows the full photofragment momentum to be used as feedback in a closed-loop adaptive control scheme, in which a genetic algorithm tailors an ultrafast laser pulse to optimize a specific outcome. Examples of three-dimensional velocity map image based control applied to strong-field dissociation of CO and O 2 are presented. © 2014 AIP Publishing LLC. [http://dx

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Pulse-shape-dependent strong-field ionization viewed with velocity-map imaging

Cited by 17 publications

References 32 publications

Strong field molecular ionization to multiple ionic states: direct versus indirect pathways

Strong field molecular ionization to multiple ionic states: direct versus indirect pathways

Adaptive strong-field control of chemical dynamics guided by three-dimensional momentum imaging

Incorporating real time velocity map image reconstruction into closed-loop coherent control

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