Figure 4: Semi-quantitative description of the independent tunability of exciton wavelength and FSS.
From: Wavelength-tunable entangled photons from silicon-integrated III–V quantum dots
(a) Matrix of polarization plots at different voltage combinations. Here the exciton energy is plotted as a function of θ, with the same definition being used in the inset of Fig. 2a. All polar plots have an axis scale of 15 μeV, and the solid red lines represent a fit to the data with a sinusoidal function. The ‘circularity’ and the direction of the pedals indicate the relative amplitude of FSS and θ, respectively. Circular polarized exciton emission with zero FSS can be observed at three different voltage combinations, that is, at different exciton emission wavelength. No appreciable polarization rotation can be observed at the applied voltages. The schematic shows the stress condition for this type of QDs. (b) A density plot of the FSS as a function of the two stress magnitudes X,Y as obtained with the two-level model Hamiltonian. FSS is kept at zero for a range of stress combinations (X,Y), therefore the wavelength at which FSS is zero can be tuned at will.
