Exciton fine structure splitting in dot-in-a-well structures

A range of dot-in-a-well structures designed for long-wavelength (>1.3μm) emission is studied in polarization- and time-resolved differential transmission measurements. Quantum beats observed in differential transmission are employed to measure the fine structure splitting (EFS) of the bright exciton states. A strong dependence of EFS on In content in the InGaAs well surrounding the dots is observed. Large magnitudes of EFS up to 87μeV are found.

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