Extended Data Fig. 3: Spectroscopy on cavity-coupled QD1.
From: A gated quantum dot strongly coupled to an optical microcavity
a, X0 at B = 0.00 T. RF scan revealing two transverse-electromagnetic (TEM00) cavity modes with a polarization splitting of 25 GHz (inclined lines) coupled to two FSS levels of X0 with a splitting of 1 GHz (horizontal lines). b, Line cut at resonance with the ‘left’ cavity mode (as indicated by red arrow). The main peaks arise from coupling of the ‘high’-frequency X0 transition to one cavity mode; the peak at ΔL = 0 arises from coupling of the ‘low’-frequency X0 transition to the same cavity mode. c, g(2)(0) versus laser detuning for a cavity detuning close to zero. d, Power dependence at resonance. Excitation of the second rung of the Jaynes–Cummings ladder (LP2, UP2) is evident at high powers, as indicated by the dashed vertical lines. e, X0 at B = 0.40 T. RF scan revealing that the same TEM00 cavity modes couple to the two X0 transitions. The X0 transitions are now separated by Zeeman splitting. f, Line cut at resonance with the ‘left’ cavity mode. g, h, g(2)(0) versus laser detuning for two different cavity detunings: one close to zero and one close to g. i, X+ at B = 0.00 T. RF scan of the X+ transition. j, Line cut at resonance with the ‘right’ cavity mode. k, l, Experimental (k) and theoretical (l) power dependence at resonance. The excitation of higher rungs of the Jaynes–Cummings ladder is evident by the convergence from the two first-rung polaritons towards the bare-cavity mode with increasing power, leading to a calculated mean photon number in the cavity of up to ⟨n⟩ = 16. The Hilbert space in the model is truncated to 35 rungs of the Jaynes–Cummings ladder. The slight frequency shift of the signal peak in k at maximum laser power is due to an unintended drift of the cavity length during this experiment. In all figures, the vertical lines depict the resonance frequencies for the first three rungs of the Jaynes–Cummings ladder (LP1, UP1: solid; LP2, UP2: dashed; LP3, UP3: dotted) at a particular cavity detuning. Error bars in c, g, h are one standard error.
