In the case of linear molecules, the laser-induced orientation is transient and disappears shortly after the excitation, typically within several hundreds of femtoseconds. The question is whether a long-lasting orientation is possible, i.e., on a nanosecond time scale or even longer. The answer is yes, but only for non-linear molecules, the so-called symmetric- or asymmetric-tops.
Differentiation and separation of molecular enantiomers in a mixture are important and challenging problems. While many physical properties are identical in the two enantiomers, their biological activities are often markedly different. We use strong nonresonant laser fields with twisting polarization to selectively control the rotations of chiral molecules in the gas phase.
When linearly polarized light is transmitted through a rotating dielectric, the polarization plane is slightly rotated—a phenomenon first studied by Fermi in 1923. We showed that this effect may be dramatically enhanced if the light is sent to a gas of fast unidirectionally spinning molecular super-rotors.
Echo in mountains is a well-known phenomenon, where an acoustic pulse is mirrored by the rocks, often with reverberating recurrences. Over the years, we studied various echo phenomena in the rotational and vibrational dynamics of laser-excited molecular gases, and in other quantum systems.
We theoretically study an impulsively excited quantum bouncer — a particle bouncing off a surface in the presence of gravity.
Several techniques for producing molecular movies have been proposed based on the Coulomb explosion to follow the ultrafast rotational dynamics in real time.We demonstrate a novel nondestructive optical method for direct visualization and recording of movies of coherent rotational dynamics in molecular gas.
We investigate signs of quantum chaos in a kicked quantum rotor, a linear molecule interacting with a periodic train of short laser pulses. Under certain conditions, the molecules become transparent to the laser kicks. This effect is due to a mechanism closely related to Anderson localization.
This is the question: Is there a way to make a molecule spin like a propeller using lasers? Can one create a gas sample in which the molecules rotate preferentially clock- or counterclockwise?
Molecules, unlike atoms, have an anisotropic shape, and their interaction with external fields depends on the orientation of the molecule with respect to the field and its gradient. We study how the deflection of molecules by external fields can be manipulated using additional laser pulses.
The possibility of creating molecules excited to extremely high rotational states (super rotors) enables us to explore new kinetic effects in molecular gases, including the creation of gas vortices.
The study of collisions of rarefied gas molecules with solid surfaces is an interesting and important problem. The applications range from surface analysis by Helium atom scattering to problems in aeronautics.
We revisited the problem of a kicked rotor in order to find new mechanisms for laser control of molecular rotational states, and especially for the process of molecular alignment (orientation) by laser fields.