Quantum control of molecular orientation by two-color laser fields

Abstract

We demonstrate molecular orientation by using phase-controlled two-color omega+2omega laser pulses with an intensity of 1.0x10(12) W/cm(2) and a pulse duration of 130 fs. The orientation of three iodine-containing molecules (IBr, CH(3)I, and C(3)H(5)I) was monitored by the directional asymmetries of the photofragment angular distribution in dissociative ionization. In all three molecules, the directional asymmetry showed an oscillating behavior dependent on the relative phase difference between omega and 2omega pulses. The phase dependence of the directional asymmetry observed in iodine ions and counterpart ions were out of phase with each other. This result shows that a phase-controlled omega+2omega optical field discriminates between parallel and antiparallel configurations of aligned molecules that have a permanent dipole. This method performed well because (1) molecular orientation can be achieved by all-optical fields; (2) the direction of orientation is easily switched by changing the sign of the quantum interference; and (3) this method is free from any resonance constraint and thus can be applied to any molecule.

Molecular tunnelling ionization of allyl halides induced by phase-controlled two-colour laser fields

“…Furthermore, the Cl + and Br + generated from C 3 H 5 Cl + and C 3 H 5 Br + and the I + generated from C 3 H 5 I were completely in phase with each other. (These results using gas mixtures were used in the calibration of φ [34], and are reflected in figure 4, in which the phase dependence of F + is a cosine type whereas those of Cl + , Br…”

“…In this configuration, we could simultaneously measure the phase dependence of all photofragment ions at identical φ values and laser intensities. To calibrate φ, we performed simultaneous measurements using gas mixtures of target molecules and reference C 3 H 5 I molecules [34]. This method provides an accurate phase relationship between target molecules and reference molecules under identical experimental conditions, i.e., within the same experimental run.…”

An Approach To “Quantumness” In Coherent Control

“…For example, the path alternatives are given by the two excitation processes in a 1 vs. N coherent control scenario. The resultant CCI framework is general and applicable to many systems, from atoms [15,66] to molecules [27,45,[67][68][69] to bulk solids [4,5,20,30,[70][71][72][73][74][75]. Further, the control field can be in a semiclassical coherent or in a quantum state of light, such as a multimode Fock state or a squeezed state.…”

Selective Ionization of Oriented Nonpolar Molecules with Asymmetric Structure by Phase-Controlled Two-Color Laser Fields

“…We did not use any active controls for mechanical vibrations. To compensate for the fluctuations generated from any cause, we performed simultaneous measurements between target molecules and reference molecules (CH 3 I) by using gas mixtures [12]. By sorting the data along with the reference data, the MZI effectively achieved a resolution of 30 asec.…”

“…The experimental apparatus, which has been described previously [12], consisted of a Ti:sapphire laser system, a Mach-Zehnder interferometer (MZI), and an ion time-offlight (TOF) mass spectrometer. Here, we have added supplementary information, especially about how to handle the 130-fs, !…”