Landolt-Börnstein - Group III Condensed Matter

1.2 Theory of stationary spectroscopy

Abstract

This chapter discusses the theory of stationary spectroscopy under four major sections headings, namely, (i) optical transitions, semiconductor Bloch equations, and linear spectra, (ii) plasma-density-dependent spectra, (iii) electro-optical spectra, and (iv) magneto-optical spectra. The electronic states of quantum confined structures between which the optical transitions can take place are given by a mixture of discrete subband quantum numbers and a d-dimensional continuous momentum vector. The optical transitions are governed by the single-particle reduced density matrix. If a strong pump pulse excites an e-h plasma it will relax to quasi-equilibrium thermal distributions both in the conduction and valence bands by carrier-carrier scattering and by scattering with optical phonons in less than a picosecond. Because the lifetime of the e-h carriers is in direct gap semiconductors typically in the order of nanoseconds, there is a long time interval in which the linear spectra of a test beam are determined by a semiconductor with a thermal high-density electron-hole plasma. In semiconductor microstructures the modifications of the optical spectra by a static electric field F0 applied perpendicular to confining potential walls are very different from the Franz-Keldysh effect in bulk semiconductors. Because of the opposite charges, the field pushes the electron and hole toward the opposite potential walls. Hence the overlap between the corresponding particlein-a-box wave functions is drastically modified. The effect of a static magnetic field B perpendicular to the quantum well plane is particularly strong, because the magnetic field forces the carriers in the well layer into quantized cyclotron orbits.

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Title
1.2 Theory of stationary spectroscopy
Book Title
Optical Properties. Part 1
In
1 Theoretical concepts
Book DOI
10.1007/b55683
Chapter DOI
10.1007/10479578_4
Part of
Landolt-Börnstein - Group III Condensed Matter
Volume
34C1
Editors
  • C. Klingshirn
  • Authors
  • H. Haug
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