Control of elliptical high-order harmonics and attosecond pulses from H 2 + in an orthogonally polarized two-color laser field

Abstract This study explores the generation of high-order harmonics (HHG) and ultrashort-isolated attosecond pulses (IAPs) by driving the H 2 + with an orthogonally polarized two-color (OTC) field. Using numerical simulations by solving the two-dimensional time-dependent Schrödinger equation (2D-TDSE), the research provides an in-depth analysis of the harmonic characteristics and their dependencies during this process. The results indicate that the ellipticity of the high-order harmonics is significantly influenced by the frequency ratio, intensity ratio, and alignment angle of the OTC field. Under specific parameter combinations, the H 2 + molecule in an OTC field can produce nearly circularly polarized attosecond pulses, with an ellipticity of up to 0.97 and a pulse width of 301 attoseconds. This finding highlights the potential of tuning OTC field parameters to generate highly elliptically polarized attosecond pulses, offering crucial theoretical support and technical feasibility for future applications in high-precision, short-duration polarized attosecond light sources.