Control of the emission channels energy flow in a nonlinear laser-potassium atom interaction

A numerical study of the emissions of a four-level potassium atom excited either by a single pulse or by a pair of temporally separated pulses is presented. For a low-intensity single-pulse two-photon excitation (|4S1/2〉↔|6S1/2〉), parametric emissions along path-1 (|6S1/2〉↔|5P3/2〉↔|4S1/2〉) are generated while along path-2 (|6S1/2〉↔|4P3/2〉↔|4S1/2〉) are essentially inactive. But for high single-pulse excitation, the path-1 emissions saturate and delayed path-2 amplified spontaneous emissions appear. It is shown that in the case of a double-pulse excitation scheme, proper temporal separation of the pulses and saturation of path-1 emissions caused by the first pulse can be applied to selectively transfer the excitation energy from path-1 to path-2 emissions.