Figure 3: Independent tunability of exciton wavelength and FSS.
From: Wavelength-tunable entangled photons from silicon-integrated III–V quantum dots
(a) FSS is plotted as a function of the exciton wavelength λX (energy EX), at different values of VBD. The solid lines are theoretical fits. In the k·p theory we consider the effect of a pair of orthogonal uniaxial stresses applied to an aligned QD. Exciton energy at which FSS ∼0 is tuned by 3.7 meV. The dashed line is a threshold of 1 μeV for the entangled photons generations. For FSS of below 1 μeV, the error bars of ±0.25 μeV are indicated (Methods section). (b) Polarization correlation spectroscopy, Methods section, is performed on the biexciton and exciton photons, when the QD FSS is tuned to zero. The normalized coincident counts are given for both co-polarized and cross-polarized photons. We have measured a fidelity f+ of 0.733±0.075 without any background subtraction. The two dashed lines indicate the threshold of 0.5 for the classically correlated light, and the threshold of 0.25 for the uncorrelated light.
