Enantiomeric purification of nonpolarized racemic mixtures using coherent light

Abstract

Absolute asymmetric synthesis from an isotropic racemic mixture of chiral molecules with the help of their laser orientation-dependent selection Angular momentum constraints for coherently controlling chiral purification of racemic mixtures using the dipole-electric field interaction are examined in detail for two different scenarios. First shown is that achieving enantiomeric control in our earlier scheme ͓M. Shapiro, E. Frishman, and P. Brumer, Phys. Rev. Lett. 84, 1669 ͑2000͔͒, using parallel laser pulses, requires that the system be M-polarized, where M is the projection of the total angular momentum along the axis of laser polarization. An alternate scenario is then introduced that allows chiral control in an unpolarized racemic mixture by using three mutually perpendicular linearly polarized light fields. Analytic expressions for the enantiomeric excess in both cases are derived and computational results are presented.a property that follows from the basic relation, ID ,M J ͑ ,,͒ϭ͑Ϫ1͒ Jϩ D Ϫ,M J ͑ ,,͒. Given the above rotational wave functions, the wave functions in the ground electronic state are written as ͉L p ͘ϭ͉v L ͘D ,M J,p , ͉D p ͘ϭ͉v D ͘D ,M J,p , ͑15͒and the excited state wave functions are written ͑see Fig. 1͒ as,

Ultrafast adaptive optical near-field control

“…Such light fields have potential applications in molecular coherent control 42 and, in particular, chirality control. [43][44][45] More generally speaking, three-dimensionally shaped light fields offer the possibility for controlling vectorial properties of light-matter interaction on a fundamental level. Furthermore, the field properties can be changed on length scales smaller than extended quantum wave functions.…”

Adaptive Femtosecond Quantum Control

“…This opens the door to a number of qualitatively new experimental schemes, which exploit the full vectorial temporal response of quantum systems. It allows to address stereochemical aspects in quantum control such as chiral selectivity, where polarization-shaped laser pulses are a crucial ingredient [31][32][33][34][35][36]. The optical control of lattice vibrations [156] and the generation and characterization of attosecond light pulses [130,131] are further examples of numerous new perspectives.…”

“…Moreover, as both µ(t) and E(t) are vectorial quantities, it is apparent that the polarization of the electric field can significantly influence the outcome of a given process. In recent years it has been shown by Brumer, Shapiro and coworkers [31,32], by Bychkov et al [33] and by Fujimura, Manz and coworkers [34][35][36] that the manipulation of the polarization state of the control field is a crucial ingredient for achieving selectivity in chiral systems. Chapters 3.4.2 and 5 deal with the questions how such time-dependent polarization profiles can be generated in the near-IR, and how they can be transferred to the visible/UV spectral range.…”

“…This reorientation is accompanied by a change of the projection of the electric dipole moment of the molecules along the y-axis, which results in a change of the dielectric tensor ε and hence a change of the index of refraction n y in the y-direction. By applying an appropriate voltage U it is therefore possible to adjust the refractive index and thereby the phase ∆φ that is accumulated by the light passing through the pixel: 32) where d is the spacing of the substrates and ω is the frequency of the incident light. In order to determine ∆φ (U, ω), it is necessary to perform two calibration measurements, which are described in detail in Ref.…”

“…The application of time-dependent polarization states that can thus be generated has been suggested, for example, for the generation [130,131] and characterization [132] of attosecond light pulses, for the optical control of lattice vibrations [133] and the selective production of enantiomers [31][32][33][34][35][36]. The adaptive shaping of complex polarization profiles within a learning loop has been demonstrated by our group in an optical demonstration experiment [134], and Oron et al have used spectral modulation of phase and polarization direction in coherent anti-Stokes Raman spectroscopy (CARS) [135].…”