Figure 1

(a) Schematic of the micro-photoluminescence measurement and two-color photoluminescence imaging setup. (b–e) Method to acquire the relative position of the QD: (b) EMCCD image of the alignment marks when focusing on the surface. (c) EMCCD image of the photoluminescence from a single QD when focusing on the QD layer that is at the center of λ-GaAs cavity (≈1.85 μm below the surface). (d,e) x(y) axis line cut along the horizontal(vertical) dot line in (b) and (c), showing the QD emission, light intensity reflected by metallic marks. Herein, the Lorenz fit (red lines) and Gaussian fits (blue lines) are used to determine the location of the QD and the center position of alignment mark, respectively. The positions are then translated from a pixel value on the images to a distance on the sample by counting the number of pixels between two nearby marks with known distance. (f) Histograms of the uncertainties of the QD and alignment mark positions and QD-alignment mark separations (47 images). The uncertainties represent one standard deviation values determined by a nonlinear least squares fit of the data.