title: Incorporating real time velocity map image reconstruction into closed-loop coherent control.
abstract: 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 two-dimensional momentum projection from the detector must be inverted to reconstruct the full three-dimensional 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 O2 are presented.
authors.affiliation: Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Rallis
authors.affiliation: Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA.
authors.forename: T G
authors.initials: TG
authors.lastname: Burwitz
authors.affiliation: Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA.
authors.forename: P R
authors.initials: PR
authors.lastname: Andrews
authors.affiliation: J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: M
authors.initials: M
authors.lastname: Zohrabi
authors.affiliation: Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA.
authors.forename: R
authors.initials: R
authors.lastname: Averin
authors.affiliation: J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: S
authors.initials: S
authors.lastname: De
authors.affiliation: Max Planck Institute of Quantum Optics, Hans-Kopfermann Strasse 1, D-85748 Garching, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Bergues
authors.affiliation: Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA.
authors.forename: Bethany
authors.initials: B
authors.lastname: Jochim
authors.affiliation: Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA.
authors.forename: A V
authors.initials: AV
authors.lastname: Voznyuk
authors.affiliation: Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA.
authors.forename: Neal
authors.initials: N
authors.lastname: Gregerson
authors.affiliation: J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: B
authors.initials: B
authors.lastname: Gaire
authors.affiliation: Max Planck Institute of Quantum Optics, Hans-Kopfermann Strasse 1, D-85748 Garching, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Znakovskaya
authors.affiliation: J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: J
authors.initials: J
authors.lastname: McKenna
authors.affiliation: J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: K D
authors.initials: KD
authors.lastname: Carnes
authors.affiliation: J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Kling
authors.affiliation: J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: I
authors.initials: I
authors.lastname: Ben-Itzhak
authors.affiliation: Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA.
authors.forename: E
authors.initials: E
authors.lastname: Wells