Selective ionization of oriented molecules by phase-controlled laser fields

Intense (1012-1013 W/cm2) phase-controlled laser fields consisting of a fundamental light and a second-harmonic light induce the directionally asymmetric tunneling ionization and the resultant selective ionization of oriented molecules. It is demonstrated that selective ionization of oriented molecules induced by phase-controlled ω + 2ω laser fields reflects the geometric structure of the highest occupied molecular orbital. This method was robust, being free of both laser wavelength and pulse-duration constraints, and thus can be applied to a wide range of molecules.