A single isolated sub-50 attosecond pulse generation with a two-color laser field by a frequency-chirping technique

► Two-color laser field with frequency chirping technique ionizing He atom. ► Solution of the time-dependent Schrödinger equation. ► The optimized best condition of using the same chirping in both of the laser fields. ► Generation of a single isolated attosecond pulse of 48 as without phase compensation.