Figure 4. Experimental demonstration of spin readout in photonic crystal waveguides.

(a) Photoluminescence spectra of QDs with high contrast in PhC WGs. (b) Experimental photoluminescence spectra of QDs with low contrast in PhC WGs. Fitted peaks in a and b are shown with orange curves. (c) Readout contrast C=(I_σ+−I_σ−)/(I_σ++I_σ−) for left and right out-couplers for randomly distributed self-assembled QDs in PhC WGs (35 QDs). The points correspond to experimental data, and the black diagonal line shows the expected distribution for ideal circularly polarized dipoles. (d) Statistical distributions of the absolute average contrasts C=(|C_LEFT|+|C_RIGHT|)/2 of QD spin readout taken from the experimental data in c for PhC WGs. All experimental data are recorded at B_Z=1 T. (e) Simulated statistical distributions of absolute contrasts calculated from the coupling of circularly polarized dipoles distributed across the WGs in the xy-plane (z=0) taking into account the electric field distributions (Supplementary Note 4) due to the out-couplers for PhC WGs. The inset in c shows schematic of the PhC WGs.