Ultrafast module

In this chapter, we have expounded our comprehensive approach to the dynamical control of decay and decoherence. Our analysis of dynamically modified coupling between a qubit and a bath has resulted in the universal formula (4.49) for the dynamically modified decay rate into a zero-temperature bath, as well as its counterparts (4.114) for excited- and ground-state dynamical decay into finite-temperature baths. This ground-state dynamically induced decay results from RWA violation by ultrafast modulation. 

Here Hs(t) is the driven (and modulated) system Hamiltonian, S(t) is a system operator and B(t) is a bath operator, whose choice depends on the system-bath coupling (linear or quadratic, diagonal or off-diagonal). These operators vary with time due to the external fields. This general form of ///(/.), unlike common treatments, does not invoke the RWA, [Cohen-Tannoudji 1992], which may fail for ultrafast modulation. The combined state of the system and the bath is described by the density matrix ps+B(t). 

Bicchi, C., C. Brunelli, C. Cordero, P. Rubiolo, M. GaUi, and A. Sironi, 2004. Direct resistively heated column gas chromatography (ultrafast module-GC) for high-speed analysis of essential oils of differing complexities. J. Chromatogr. A, 1024 195. 

In order to directly probe the dynamics of CT between Et and ZG, and to understand how the intervening DNA base stack regulates CT rate constants and efficiencies, we examined this reaction on the femtosecond time scale [96]. These investigations revealed not only the unique ability of the DNA n-stack to mediate CT, but also the remarkable capacity of dynamical motions to modulate CT efficiency. Ultrafast CT between tethered, intercalated Et and ZG was observed with two time constants, 5 and 75 ps, both of which were essentially independent of distance over the 10-17 A examined. Significantly, both time constants correspond to CT reactions, as these fast decay components were not detected in analogous duplexes where the ZG was re-... 

Fig. 3.9. Left photoelectron intensity from TbTe3 surface as a function of energy and momentum for different time delays, showing the ultrafast closing of the CFW gap marked with a dot. Right Time-dependent binding energy of the Te band (lower trace) and the CB (upper trace), exhibiting a periodic modulation at 2.3 and 3.6 THz, respectively, under strong excitation fluence (2mJ/ cm2). From [22]...

Figure 6.10 Ultrafast efficient switching in the five-state system via SPODS based on multipulse sequences from sinusoidal phase modulation (PL). The shaped laser pulse shown in (a) results from complete forward design of the control field. Frame (b) shows die induced bare state population dynamics. After preparation of the resonant subsystem in a state of maximum electronic coherence by the pre-pulse, the optical phase jump of = —7r/2 shifts die main pulse in-phase with the induced charge oscillation. Therefore, the interaction energy is minimized, resulting in the selective population of the lower dressed state /), as seen in the dressed state population dynamics in (d) around t = —50 fs. Due to the efficient energy splitting of the dressed states, induced in the resonant subsystem by the main pulse, the lower dressed state is shifted into resonance widi die lower target state 3) (see frame (c) around t = 0). As a result, 100% of the population is transferred nonadiabatically to this particular target state, which is selectively populated by the end of the pulse.

Note that SPODS is nearly always operative in resonant strong-held excitation using modulated ultrashort laser pulses, the only exception being so-called real laser pulses [72, 77] (i.e., electric helds with only one quadrature in the complex plane) that are usually hard to achieve in ultrafast laser technology. This is why many different pulse shapes can lead to comparable dressed state energy shifts and... 

B. All-Optical Ultrafast Spatial Light Modulation and Parallel Optical Recording Based on Photoinduced Complex Refractive Index Changes in Guided Wave Geometry Containing Organic Dyes... 

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