• Coherent nonlinear spectroscopy with shaped femtosecond pulses
  

  Coherent anti-Stokes Raman Scattering

 Traditional methods of nonlinear laser spectroscopy rely on the coherence of laser pulses as it determines the resolution of a spectroscopic measurement. We have developed a new spectroscopic method in which noise and decoherence are introduced deliberately to increase spectral resolution, robustness and efficiency of CARS. Our approach combines the efficiency and resolution of a coherent process with the robustness of incoherent light, and can be implemented in a simple optical setup because it relies on random noise rather than on an accurate spectral or temporal pulse shaping.

• Adiabatic control of quantum wave packets
  

  Piecewise Adiabatic Passage into a coherent state superposition

The method of piecewise adiabatic passage allows us to match the temporal profile of the excitation field to the internal molecular dynamics, and as a result, to populate efficiently complex wavepackets instead of a single quantum state. The complexity of the excited wavepackets, e.g. the relative amplitudes and phases of the participating eigenstates, can be further controlled by the spectral shaping of the excitation pulses, thus enabling state-selective chemistry. Efficient population transfer into a particular set of states among many available molecular levels is also important for many applications of coherent control in cold molecules and the realization of quantum computing operations.

• Laser control of molecular rotation
  

  Laser spinning of molecular isotopes

Trains of ultrashort laser pulses separated by the time of rotational revival (typically, tens of picoseconds) have been exploited for creating ensembles of aligned molecules. In this work we introduce a \textit{chiral pulse train} - a sequence of linearly polarized pulses with the polarization direction rotating from pulse to pulse by a controllable angle. The chirality of such a train, expressed through the period and direction of its polarization rotation, is used as a new control parameter for achieving selectivity and directionality of laser-induced rotational excitation. The method employs chiral trains with a large number of pulses separated on the time scale much shorter than the rotational revival (a few hundred femtosecond), enabling the use of conventional pulse shapers.