Adiabatic Passage in Multilevel Systems with Frequency - Optical Pulses: Efficiency and Selectivity of Population Transfer.

Fatemeh Ahmadinouri, Mehdi Hosseini, Farrokh Sarreshtedari

李小红, Xianzhou Zhang, Zhang Rui-Zhou +1 more

Using the time-dependent multilevel approach, we have calculated the coherent population transfer between the quantum states of potassium atom by a single frequency-chirped laser pulse. The result shows that a pair of sequential 'broadband' frequency-chirped laser pulses can efficiently transfer population from the initial state of the ladder system to the target state. It is also found that the population can be efficiently transferred to a target state and trapped there by using an 'intuitive' or a 'counterintuitive' frequency sweep laser pulse in the case of 'narrowband' frequency-chirped laser pulse. Our research shows that the complete population transfer is related to the pulse duration, chirp rate, and amplitude of the laser pulse.

Eugeny Korsunsky

Joseph S. Melinger, Suketu R. Gandhi, Anand Hariharan +2 more

We present detailed experimental and theoretical results on population transfer with frequency-swept picosecond laser pulses. Here, we demonstrate that intense frequency-swept pulses, when applied in the adiabatic limit, lead to both more efficient and more selective excitation than do unmodulated laser pulses. The experimental work is performed on quasi-two-level systems (pentacene/p-terphenyl crystal and Na vapor), quasi-three-level systems (Na vapor), and on more complex multilevel systems (I2 vapor). We discuss the different characteristics of adiabatic population transfer in both few-level, and multilevel cases, and, in particular, present computer calculations to explore the effects of molecular rotations in multilevel adiabatic population transfer.

J. Oreg, F. T. Hioe, Joseph H. Eberly

Zhenhua Zhang, Xihua Yang, Xiaona Yan

We present a way to realize selective, robust, and efficient population transfer in a ladder-type four-level system with an equally populated doublet in the initial state. By merging stimulated Raman adiabatic passage and chirped adiabatic passage techniques, we show that selective and complete population transfer from either of the initial doublet levels to the final state can be achieved with chirped pump and Stokes pulse pairs when the spectral resolution constraint of a frequency swept pulse holds (the energy separation of doublet levels should be much larger than the pulse bandwidth). We further demonstrate that the spectral resolution of selective population transfer can be enhanced significantly by using pump pulse pair and Stokes pulse due to temporal quantum interference between the sequential transitions in the time domain, which can also be well followed as a result of the frequency-domain formation of a comblike structure of the pulse pair spectrum. The proposals take into account the case of population transfer in realistic atomic and molecular systems, and may have applications in quantum coherent control of systems with equally populated initial manifolds.