Spectral analysis of high-order harmonic generation in carbon plasma using linearly, radially, and azimuthally polarized femtosecond pulses

Abstract

We demonstrate high-order harmonic generation in carbon plasma using linearly, radially, and azimuthally polarized beams from a femtosecond laser (1030 nm, 40 fs, 50 kHz). The conditions for carbon plasma formation during laser ablation were optimized by adjusting the heating pulse energy in the cases of the single-color (1030 nm) and two-color (1030 nm + 515 nm) pump schemes to generate harmonics up to the 39th order. The application of radial and azimuthally polarized annular single-color (1030 nm) beams at optimal conditions of plasma formation allowed the demonstration of the spectral division and inclination of the vector harmonics. An asymmetric distribution of harmonics was obtained using the vortex beam generated during the propagation of laser radiation through the quarter-wave plate and S-waveplate.