Inversion produced and reversed by adiabatic passage

Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

“…With proper focusing and sufficient infrared power, complete population transfer is achieved by rapid adiabatic passage between the initial and final ro-vibrational levels that are connected by the IR field. 26 Without focusing, the population of the initial and final state connected by the coherent IR field will undergo Rabi-cycling while molecules are traversing the IR beam. The final population in the vibrationally excited state will be a sensitive function of the laser intensity, the transit time, and the transition dipole moment of the ro-vibrational transition.…”

Quantum state specific reactant preparation in a molecular beam by rapid adiabatic passage

“…By sweeping the frequency of the excitation field across the molecular resonance it is possible to achieve a level crossing for a two level system in the presence of a resonant electromagnetic field. 12 If the frequency sweep is sufficiently slow, adiabatic following occurs resulting in complete population transfer from the ground to the excited state. [10][11][12] The creation of this population inversion is relatively insensitive to precise experimental conditions including the velocity of the molecules, changes in laser intensity and the different transition strengths corresponding to degenerate m sublevels in a given J level, making this a widely applicable method for obtaining complete population transfer.…”

“…12,14 First, the frequency sweep rate has to be sufficiently slow to ensure an adiabatic following to transfer the population from the ground state to the excited state. At the same time, the total sweep amplitude given by the product of the sweep rate and transit time must be larger than the Rabi frequency to ensure that the molecules experience a frequency sweep while passing through the laser beam that starts and ends out of resonance.…”

“…A more robust method for creating a population inversion is through rapid adiabatic passage (RAP), 10,[12][13][14][15][16][17] as will be considered here. This technique has previously been described theoretically 10,12,18 and demonstrated experimentally in atomic systems including metastable helium 17 and dysprosium.…”

“…This technique has previously been described theoretically 10,12,18 and demonstrated experimentally in atomic systems including metastable helium 17 and dysprosium. 16 RAP has also been demonstrated for molecules such as SF 6 19 and C 2 H 4 12 where there are coincidental resonances with specific transitions of line tunable CO 2 lasers.…”