Controlling molecular scattering by laser-induced field-free alignment

Abstract

We consider deflection of polarizable molecules by inhomogeneous optical fields, and analyze the role of molecular orientation and rotation in the scattering process. It is shown that molecular rotation induces spectacular rainbow-like features in the distribution of the scattering angle. Moreover, by preshaping molecular angular distribution with the help of short and strong femtosecond laser pulses, one may efficiently control the scattering process, manipulate the average deflection angle and its distribution, and reduce substantially the angular dispersion of the deflected molecules. We provide quantum and classical treatment of the deflection process. The effects of strong deflecting field on the scattering of rotating molecules are considered by the means of the adiabatic invariants formalism. This new control scheme opens new ways for many applications involving molecular focusing, guiding and trapping by optical and static fields.

Rotational-State-Dependent Dispersion of Molecules by Pulsed Optical Standing Waves

“…As α eff ð10; jMjÞ ranges from 6.7 (jMj ¼ 10) to 11.5 ðjMj ¼ 0Þ × 10 −40 C m 2 V −1 , the positions of the inner and the outer singularities span from AE12 to AE35 and from AE46 to AE58 m=s, respectively. The congestions of the profiles near AE35 and AE58 m=s manifest the unimodal rainbow feature in the distribution of α eff , which was predicted by Gershnabel and Averbukh [20]. The green solid line in Fig.…”

“…Coupling between the angular and the translational motions enabled the adjustments of the deceleration by aligning the molecules with the laser field [17,18]. In addition, efficient control of molecular deflection by preshaping the angular distribution was discussed [19,20].…”

“…Thus the interaction between molecules and laser fields was recognized to be rotational-state-dependent [1,2,4,9,10,19,20,[29][30][31], and the possibility of separating quantum states with laser fields was discussed in theoretical studies [10,19,20,[29][30][31][32]. However, almost all the experimental results [2,[11][12][13][14]17,26,27] were analyzed using a single polarizability value averaged over all quantum states.…”

Efficient nonresonant dipole force on molecules by a tightly focused laser

“…Some examples include a molecule lens focusing a molecular beam [3][4][5], a molecule prism spatially separating a molecular mixture beam [6], a moving periodic optical potential slowing down or accelerating molecules [7][8][9], and correlated rotational alignment spectroscopy with aligning molecules non-adiabatically [10]. Ideas such as deflection of pre-aligned molecules were also proposed [11,12].…”

Field-free molecular alignment detection by 4f coherent imaging

“…The nonresonant interaction driven by a pulse of duration much shorter than the classical rotational period results in the production of postpulse transient molecular alignment revivals. The possibility of confining in space the rotational axes of a molecule, in the absence of strong driving field, has been found particularly useful in various fields extending to high-harmonic generation and attophysics [2], molecular tomography [3], molecular-frame photoelectron angular distribution [4], laser filamentation [5], control of molecular scattering [6], and so forth. that restricts the detection to optical methods.…”