Adiabatic population transfer by delayed laser pulses in multistate systems
Abstract
This paper analyzes the extension of the threestate process of stimulated Raman adiabatic passage to chainwiseconnected multistate systems. A necessary condition for such a process is the existence of an adiabatictransfer state, which connects adiabatically the initial state of the chain to its final state. Various counterintuitive pulse sequences are examined, in all of which the pulse that drives the last transition of the chain precedes the pulse driving the first transition, while the pulses driving the intermediate transitions may have different timings. The paper demonstrates some important qualitative differences and similarities between the systems with odd and even number of states. In the onresonance case, an adiabatictransfer state always exists for an odd number of states while it never exists for an even number of states. In the offresonance case, however, the two types of systems behave in a very similar manner and the condition for existence of an adiabatictransfer state is essentially the same. This condition, which imposes certain limitations on the laser parameters, is derived in a simple and compact form. It is also shown analytically that, besides by large detunings, the populations of the intermediate states (which are generally nonzero during the transfer) can be damped by large intermediate couplings. It is concluded that for an odd number of states, the optimal case is the onresonance one, with equal and large intermediate couplings. For an even number of states, the optimal (offresonance) case is when the intermediate couplings and the detunings have similar values. Various numerical examples of success and failure of multistate population transfer confirm the analytic conclusions.
 Publication:

Physical Review A
 Pub Date:
 September 1998
 DOI:
 10.1103/PhysRevA.58.2295
 Bibcode:
 1998PhRvA..58.2295V
 Keywords:

 32.80.Bx;
 33.80.Be;
 42.50.p;
 Level crossing and optical pumping;
 Level crossing and optical pumping;
 Quantum optics