Carrier-Envelope-Phase Dependence of Emission Properties of High-Order Harmonic Generation

The carrier-envelope-phase (CEP) dependence of the emission properties of high-order harmonic generation (HHG) are quantitatively investigated. Calculation shows that a two-cycle laser with CEP of 15° can produce a single energy distribution pulse peaked at 0.94 radian (rad) and spanned 1.29rad with the cutoff energy 2.9U_p+I_p and a bandwidth 0.86U_p (where Up is the ponderomotive potential of the laser field and I_p is the atomic ionization potential). The CEP dependence of the energy and temporal localizations of the single distribution pulse show interesting 180° periodic structures. These characteristics may be useful in optimizing attosecond x-ray sources and measurements.