Rapid adiabatic passage

The discretized adiabatic procedure, and its analog with STIRAP, is but one possibility for achieving broadband response of an optical device. An alternative, which we discuss, relies on the analogy between the Jones vector description of an optical beam and the two-state time-dependent Schrodinger equation (TDSE). This equation has two commonly used solutions. One is rapid adiabatic passage (RAP), produced by swept detuning (a chirp), and the other is Rabi oscillations, specifically a pi pulse. The RAP has theoretical connection with STIRAP, but the pi pulses have no such connections. We describe application of a procedure that has been used to extend the traditional pi pulses to broadband excitation. This can accomplish the present goal of PAP, under complementary conditions. 

V. Engel Prof. Neusser, you mentioned the technique of Stimulated Raman Rapid Adiabatic Passage STIRAP, which allows for the coherent transfer of vibrational population selectively. Is the technique not another very efficient and experimentally verified scheme of coherent control ... 

I0aO))I0a (1)) and I a(2))I0a (2))- Control is achieved by varying the four coefficients ah bj, i = 1,2. Stimulated rapid adiabatic passage (STIRAP) [245, 246] to be discussed in detail in Section 9.1, provides one choice for such state preparation. 

Inversion pulses are very important because of the wide variety of applications in experiments involving coherence selection and spin decoupling. One of the very first methods for spin inversion was the rapid adiabatic passage introduced by Bloch [18]. 

Numerous novel techniques related to STIRAP have been further developed recently. Examples are the hyper-Raman STIRAP [196, 197, 221], Stark-chirped rapid adiabatic passage (SCRAP) [222, 223], adiabatic passage by light-induced potentials [224-227], and photo-associative STIRAP, as a source for cold molecules [228-231]. Some experimental implementations of fhese ideas, e.g., fo fhe formafion of dark states in the photo-association of an afomic Bose-Einsfein Condensafe (BEC) to form a molecular BEC, have already been reporfed [232, 233]. 

L. Yatsenko, B. Shore, T. Halfmann, K. Bergmarm, A. Vardi, Source of metastable H(2s) atoms using the Stark chirped rapid-adiabatic-passage technique, Phys. Rev. A 60... 

Up to now we have only considered the population changes ANi under SEP. There are, however, also coherent effects and an even more efficient scheme for population transfer is provided by the coherent stimulated rapid adiabatic passage (STIRAP) method, explained in Chap. 7. 

M. Oberst, J. Klein, and T. Halfmarm. Enhanced four-wave mixing in mercury isotopes, prepared by stark-chirped rapid adiabatic passage. Optics Communications 2006 Aug 15 264 463-470. 

An even more efficient scheme is provided by the coherent STImu-lated Rapid Adiabatic Passage (STIRAP) method, explained in Chap. 12. 

In the adiabatic limit, t is considered to be a parameter, and is called an adiabatic state. One of the interesting properties of this limit is that a population can be inverted by evolving the system adiabatically. This process is called adiabatic passage. Population transfer induced by a laser is generally called coherent population transfer. For a two-level system, the complete population inversion is produced by a n -pulse or by adiabatic rapid passage. 

Figure 30. Selective excitation from 11 > to 2 > by the adiabatic rapid passage (ARP) in the case of three-level model. Upper part time variation of the population. Middle part-time variation of laser frequency. Bottom part-envelope of the laser pulse. Taken from Ref. [42].

Adiabatic rapid passage in molecules in solution excited by an intense ultrashort chirped pulse... 

ADIABATIC RAPID PASSAGE BETWEEN RANDOMLY FLUCTUATING LEVELS... 

In any low angular momentum state the radiative decay rate is usually dominated by the high frequency transitions to low lying states, and as a result it is impossible to control completely the decay rate using a millimeter wave cavity. In a circular i = m = n - 1 state the only decay is the far infrared transition to the n — 1 level, and Hulet et al. have observed the suppression of the decay of this level.26 They produced a beam of Cs atoms in the circular n = 22, = m = 21 state by pulsed laser excitation and an adiabatic rapid passage technique.27 The beam of circular state atoms then passed between a pair of plates 6.4 cm wide, 12.7 cm long, spaced by 230.1 jum, and held at 6 K. The 0 K radiative lifetime is 460ps, and... 

Fig. 7.6 Two Stark levels with an avoided crossing a 0. If the field is slewed through the avoided crossing in a time long compared to l/cu0 the passage is adiabatic (solid arrow), while if it is slewed rapidly through the crossing the passage is diabatic (broken arrow).

These methods provide an accurate means of investigating translation-vibration and translation-rotation transfer. The passage of a sound wave through a gas involves rapidly alternating adiabatic compression and rarefaction. The adiabatic compressibility of a gas is a function of y, the ratio of the specific heats, and the classical expression for the velocity, V, of sound in a perfect gas is... 

In the non-adiabatic regime, the time scale A"1 -C rc of the reaction is so short compared to the relaxation times of the solvent molecules that they have no chance to respond to the motion in the reaction coordinate said differently, the solvent molecules are effectively frozen in their positions during the rapid passage of the... 

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