Direct imaging of direction-controlled molecular rotational wave packets created by a polarization-skewed double-pulse

Optimization of the double-laser-pulse scheme for enantioselective orientation of chiral molecules

We present a comprehensive study of enantioselective orientation of chiral molecules excited by a pair of delayed cross-polarized femtosecond laser pulses. We show that by optimizing the pulses' parameters, a significant (~ 10%) degree of enantioselective orientation can be achieved at zero and at five kelvin rotational temperatures. This study suggests a set of reasonable experimental conditions for inducing and measuring strong enantioselective orientation. The strong enantioselective orientation and the wide availability of the femtosecond laser systems required for the proposed experiments may open new avenues for discriminating and separating molecular enantiomers.

Achieving high molecular alignment and orientation for CH[Formula: see text]F through manipulation of rotational states with varying optical and THz laser pulse parameters

Increasing interest in the fields of high-harmonics generation, laser-induced chemical reactions, and molecular imaging of gaseous targets demands high molecular "alignment" and "orientation" (A&O). In this work, we examine the critical role of different pulse parameters on the field-free A&O dynamics of the CH[Formula: see text]F molecule, and identify experimentally feasible optical and THz range laser parameters that ensure maximal A&O for such molecules. Herein, apart from rotational temperature, we investigate effects of varying pulse parameters such as, pulse duration, intensity, frequency, and carrier envelop phase (CEP). By analyzing the interplay between laser pulse parameters and the resulting rotational population distribution, the origin of specific A&O dynamics was addressed. We could identify two qualitatively different A&O behaviors and revealed their connection with the pulse parameters and the population of excited rotational states. We report here the highest alignment of [Formula: see text] and orientation of [Formula: see text] for CH[Formula: see text]F molecule at 2 K using a single pulse. Our study should be useful to understand different aspects of laser-induced unidirectional rotation in heteronuclear molecules, and in understanding routes to tune/enhance A&O in laboratory conditions for advanced applications.

Tracing the Coherent Manipulation of Rotational Dynamics by Shaped Femtosecond Pulse-Induced Two-Dimensional Rotational Coherent Spectrum

The temporal delayed orthogonal pulse pairs generated by the phase shaping technique are used to study the coherent control of the rotational wave packet dynamics in air. By continuously changing the intrapulse delay of the pump pulse, we measured the corresponding revival signals and obtained a two-dimensional rotational coherent spectrum (2D RCS). An additive property of the rotational dynamics is observed from the revival signals. Moreover, combining with the coherent control model, we find that the 2D RCS can be used to demonstrate the control over the underlying Raman rotational excitation. A beat frequency-dependent oscillation of each rotational transition is obtained. The transition process is revealed from the Fourier transformation about the pump delay. The scheme of this work can be used for further control and detection of the rotational wave packet and can be extended to other molecular dynamic researches.