Laser control response functions

The simplified theory allows the time-dependent wave function to be calculated rapidly for any specified laser field. However, controlling the dynamics of the charge carriers requires the answer to an inverse question [18-22]. That is, given a specific target or objective, what is the laser field that best drives the system to that objective Several methods have been developed to address this question. This section sketches one method, valid in the weak response (perturbative) regime in which most experiments on semiconductors are performed. 

Porous silica supports such as MCM-41 have also been employed in the development of artificial hybrid pores due to their well-defined porous network and then-facile functionalization chemistry. For instance, Lopez and coworkers employed an MCM-41 support coated uniformly with a temperature-responsive poly(AI-isopropyl acrylamide) (PNIPAAm) polymer. At low temperatures, the polymer was hydrated and extended and the pores were closed no transport of fluorescein was observed when flow cytometry and confocal laser scanning microscopy were employed. In contrast, at high temperatures the polymer was hydrophobic and collapsed, allowing the transport of the dye (Figure 24). This system thus not only acts as a temperature sensor but also shows clear features of control as will become more important in the next section. 

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