



01383nas a2200157   4500008004100000245010900041210006900150260001300219490000700232520085500239100002501094700002101119700002301140700002501163856003701188       2008                        eng d00aPhoton storage in Lambda-type optically dense atomic media. IV. Optimal  control using gradient ascent
0 aPhoton storage in Lambdatype optically dense atomic media IV Opt  c2008/4/40 v773 a  We use the numerical gradient ascent method from optimal control theory to
extend efficient photon storage in Lambda-type media to previously inaccessible
regimes and to provide simple intuitive explanations for our optimization
techniques. In particular, by using gradient ascent to shape classical control
pulses used to mediate photon storage, we open up the possibility of high
efficiency photon storage in the non-adiabatic limit, in which analytical
solutions to the equations of motion do not exist. This control shaping
technique enables an order-of-magnitude increase in the bandwidth of the
memory. We also demonstrate that the often discussed connection between time
reversal and optimality in photon storage follows naturally from gradient
ascent. Finally, we discuss the optimization of controlled reversible
inhomogeneous broadening.
1 aGorshkov, Alexey, V.1 aCalarco, Tommaso1 aLukin, Mikhail, D.1 aSorensen, Anders, S.  uhttp://arxiv.org/abs/0710.2698v2