We consider the problem of the implementation of Stimulated Raman AdiabaticPassage (STIRAP) processes in degenerate systems, with a view to be able tosteer the system wave function from an arbitrary initial superposition to anarbitrary target superposition. We examine the case a $N$-level atomic systemconsisting of $ N-1$ ground states coupled to a common excited state by laserpulses. We analyze the general case of initial and final superpositionsbelonging to the same manifold of states, and we cover also the case in whichthey are non-orthogonal. We demonstrate that, for a given initial and targetsuperposition, it is always possible to choose the laser pulses so that in atransformed basis the system is reduced to an effective three-level $\Lambda$system, and standard STIRAP processes can be implemented. Our treatment leadsto a simple strategy, with minimal computational complexity, which allows us todetermine the laser pulses shape required for the wanted adiabatic steering.
展开▼
