Polarization intraband

The laser beam at 267 nm populates a large number of excited states, each one connected with a particular conformation of the helix and vibrations of the involved chromophores (simulated by the spectral width). Most of these states are delocalized over a few bases. Then, intraband scattering takes place and emission arises from excited states located at the bottom of the exciton band these low-lying states have, in general, different polarization from the initially populated states and lead to a loss of anisotropy. Intraband scattering is obviously faster than 100 fs because, at that time, the anisotropy of the... 

Carrier relaxation due to both optical and nonradiative intraband transitions in silicon quantum dots (QDs) in SiOa matrix is considered. Interaction of confined holes with optical phonons is studied. The Huang-Rhys factor governing intraband multiphonon transitions induced by this interaction is calculated. The new mechanism of nonradiative relaxation based on the interaction with local vibrations in polar glass is studied for electrons confined in Si QDs. 

Here the averages with different wavevectors correspond to the intraband polarization, which is far off resonance and may be neglected. Since the electric field excites only states with the given total in-plane wavevector Qy, from now on we set k = Q. As a result, we obtain the equations for the polarization functions ... 

In ordinary optical absorption there are two components associated with intraband transitions (Drude component) and interband transitions, respectively. A similar situation is encountered in magneto-optical spectroscopy. Of special interest is the interband component which is related to the joint density of states. The intensity of the magneto-optical transitions is proportional to the product of spin-orbit coupling strength and net electron-spin polarization of states excited by the incident light (Erskine and Stern, 1973). 

As a consequence, the gap function il(k) is a matrix function of k only or its corresponding polar and azimuthal angles and (p. We have neglected indices for interband pairing because the available phase space is much smaller than in the case of intraband pairs. 

Equations (6.17)-(6.20) can be easily generalized again for the case of two macromolecules. If only their valence and conduction bands are again taken into account and the case of partially filled bands considered, one finds once more that due to the much smaller intraband excitation energies e /(A , k ) and e (k2- k 2), the contribution of these excitations to the polarization term will be dominant. 

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