Adaptive control of molecular alignment

Abstract

We demonstrate control on nonadiabatic molecular alignment by using a spectrally phase-shaped laser pulse. An evolutionary algorithm in a closed feedback loop has been used in order to find pulse shapes that maximize a given effect. In particular, this scheme has been applied to the optimization of total alignment, and to the control of the temporal structure of the alignment transient within a revival. Asymmetric temporal pulse shapes have been found to be very effective for the latter and have been studied separately in a single-parameter control scheme. Our experimental results are supported by numerical simulations.

Strategies for efficient field-free molecular alignment and its control

“…The problem of optimizing the degree of alignment in field-free conditions is intensively studied [13][14][15][16]. One important practical constraint is to prevent the ionization of the molecule by limiting the intensity of the fields.…”

Coherent rotational dynamics of molecules in intense laser field

“…Second, molecules in highly anisotropic states exerted to NAREX will be particularly useful for studies on, e.g., quantum-state resolved collision or reaction dynamics. Third, NAREX can become a competent tool for changing and controlling the rotational state distribution of molecules, especially when recent elaborate methods, i.e., double-pulse pair [7][8][9] and shaped pulse, 10,11 are invoked.…”

Even harmonics from laser driven homonuclear molecules

“…The superposition of high frequency components with well-defined phase is the road to very short pulses; the large cutoff frequency makes molecules apt to form electromagnetic pulses lasting a very few laser periods; in the following the optical cycle (oc) of the driving laser will be considered as the natural unit of time. Furthermore, heteronuclear molecules do not present a number of spatial symmetries and can generate even harmonics; the state of the experimental art makes it possible to align and orient molecules along a desired direction [12,13] so that no local averaging can re-establish the parity and wash out the production of even-order harmonics [14].…”