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150 - I. G. Lang , S. T. Pavlov 2010
The light reflectance and absorbance are calculated for a quantum well (QW) the width of which is comparable with the light wave length. The difference of the refraction coefficients of the quantum well and barriers is taken into account. The stimula ting pulse form is arbitrary. An existence of two closely situated discrete excitation energy levels is supposed. Such energy level pare may correspond to two magnetopolaron states in a quantizing magnetic field perpendicular to the QW plane. The relationship of the radiative and non-radiative damping is arbitrary. The final results does not use the approximation of the weak Coulomb interaction of electrons and holes.
Reflectance, transmittance and absorbance of a symmetric light pulse, the carrying frequency of which is close to the frequency of interband transitions in a quantum well, are calculated. Energy levels of the quantum well are assumed discrete, and tw o closely located excited levels are taken into account. The theory is applicable for the quantum wells of arbitrary widths when the size quantization is preserved. A distinction of refraction indices of barriers and quantum well is taken into account. In such a case, some additional reflection from the quantum well borders appears which changes essentially a shape of the reflected pulse in comparison to homogeneous medium. The reflection from the borders disappears at some definite ratios of the carrying frequency of the stimulating pulse and quantum well width.
Reflectance, transmittance and absorbance of a symmetric light pulse, the carrying frequency of which is close to the frequency of interband transitions in a quantum well, are calculated. Energy levels of the quantum well are assumed discrete, and tw o closely located excited levels are taken into account. A wide quantum well (the width of which is comparable to the length of the light wave, corresponding to the pulse carrying frequency) is considered, and the dependance of the interband matrix element of the momentum operator on the light wave vector is taken into account. Refractive indices of barriers and quantum well are assumed equal each other. The problem is solved for an arbitrary ratio of radiative and nonradiative lifetimes of electronic excitations. It is shown that the spatial dispersion essentially affects the shapes of reflected and transmitted pulses. The largest changes occur when the radiative broadening is close to the difference of frequencies of interband transitions taken into account.
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