Efficient Coherent Population Transfer among Three States in NO Molecules by Stark-Chirped Rapid Adiabatic Passage

We present the experimental demonstration of a novel, efficient, and selective technique to prepare population inversion. The technique is an extension of Stark-chirped rapid adiabatic passage (SCRAP), i.e., SCRAP among three states. In this process a $\Lambda$-type quantum system is driven by two laser pulses, the pump and Stokes pulses, which are appropriately detuned from transition frequencies. A third laser pulse induces a dynamic Stark shift in the upper energy level, and the timing of all three pulses is controlled in order to prepare population inversion between the two lower states in the $\Lambda$-type level scheme. Our data on population transfer in nitric oxide (NO) molecules clearly show that SCRAP among three states provides an advantageous alternative to such techniques as stimulated Raman adiabatic passage.

Figure 1

Coupling scheme for population transfer by SCRAP among three states in nitric oxide (NO) molecules.

Figure 2

Excitation by D-SCRAP: experimentally obtained population of the target state $|3⟩$, when the pump and Stokes laser detunings are varied. The solid, white line indicates the two-photon resonance between the states $|1⟩$ and $|3⟩$.

Figure 3

Excitation by T-SCRAP: experimentally obtained population of the target state $|3⟩$. Compare caption of Fig. 2.