Fig. 2: Time-resolved PL measurements for the non-chiral QD.

a Non-resonant excitation scheme. b Quasi-resonant phonon-sideband excitation scheme. The grey box shows the spectral density of the phonon states by using a gradient fill so that the grey fades out as we get further away from the transition in energy. c Lifetime measurement for a tuned QD at the slow-light region (dark dots, V = 0 V, B = −4.5 T) under quasi-resonant phonon-sideband excitation. The solid red curve represents a single exponential fit. For the quasi-resonant excitation, a small laser detuning of 2 meV was used to excite the phonon-side band of the QD line. That gave a very fast (few ps) relaxation and thus revealed a radiative decay time of 60 ± 6 ps. The light green line shows photoluminescence decay of the QD ensemble in bulk measured with non-resonant excitation. The dark green line represents the instrument response function (IRF, FWHM = 20 ps). d Wavelength dependency of the Purcell factor of the QD coupled to the slow-light PCW. The red and blue dots represent measured data under non-resonant above-band (808 nm) and phonon-sideband excitation schemes, respectively. The inset shows the PL scan for the coupled QD versus voltage.