Molecular high-order harmonic generation by counter-rotating elliptically polarized intense pulses

Abstract

We present a scheme to produce the selected left or right elliptically polarized high-order harmonic generation. By adopting bichromatic counter-rotating colinear elliptically polarized pulses, their interaction with oxygen molecule are calculated under the framework of time-dependent density functional theory. Here we show that the helicity-selective high harmonics with tunable ellipticity are generated by changing the ellipticity of one of the pump pulses. Because of the interference of the degenerate highest occupied molecular orbitals, tunable ellipticity in a wide spectral range is obtained. This scheme can be used to synthesize attosecond pulses with controlled ellipticity and helicity.

Yield enhancement of elliptical high harmonics driven by bicircular laser pulses

“…Recently, another 2D synthesized driving field, i.e., the bicircular laser field (BLF), has attracted a great deal of attention [28][29][30][31][32][33][34][35][36][37][38][39] due to two features of the harmonics generated by this field. One is that the conversion efficiency of HHG does not need to be compromised.…”

“…In order to generate elliptically polarized attosecond pulses by the BLF scheme, one can break the symmetry of the interaction systems. For example, one can prepare the molecules as the targets of interaction [35,37,38] and adjust the two BLF components. [39,40] In order to accurately control the yield and polarization of HHG, the correspondence between harmonics and electron trajectories in the interaction of molecules and BLFs with different intensity ratios needs to be established.…”