Robust quantum control of molecular tunneling ionization in the space domain by phase-controlled laser fields

Abstract

Quantum control of a system with coherent laser fields involves not only a time-domain component but also a space-domain component. Here we used phase-controlled laser fields to achieve quantum control of tunneling ionization in the space domain and the resultant selective ionization of oriented molecules in the gas phase. The directionally asymmetric tunneling ionization induced by intense (5.0x10{sup 12} W/cm{sup 2}) nanosecond phase-controlled fields consisting of a fundamental light and second-harmonic light led to selective ionization of oriented molecules, which reflects the geometric nature of the highest occupied molecular orbital in the ground state. High selectivity was achieved with a single control variable. Quantum control was robust, being free of both laser wavelength and pulse-duration constraints, and thus can be applied to a wide range of molecules. Moreover, the combination of a conventional laser source and an adjustment-free simple optical system provided robust quantum control with high reproducibility.