Single circularly polarized attosecond pulse generation by spatially inhomogeneous fields from atoms with nonvanishing angular quantum number

We address an efficient scheme to generate single circularly polarized attosecond pulse using spatially inhomogeneous fields in the vicinity of metallic nanostructures from atom media with nonvanishing angular quantum number. Based on the numerical solution of a two-dimensional time-dependent Schrödinger equation, it is shown that using linearly polarized plasmonic fields, the harmonic intensity of two orthogonal polarization components, i.e., harmonics polarized parallel and perpendicular to the driving fields polarization direction, is comparable. Moreover, the relative phase between the two components is about π/2. As a result, near-circularly polarized isolated attosecond extreme ultraviolet or X-ray pulses can be directly produced.