a, Colour map plot for g(2)(0) obtained in the photon blockade regime for 1.6<κ/2π[GHz]<16 (that is, 104<Q<105) and 16<g/2π[GHz]<64. b, Plot of g(2)(0) versus probe laser detuning for four relevant cases. κ/2π=16 GHz (Q=104), g/2π=16 GHz (red line) corresponds to the system reported in this letter. κ/2π=6.37 GHz (Q=25,000), g/2π=16 GHz (black dotted line) is for a system with coupling strength similar to the one in this letter but with the highest Q measured in our laboratory. κ/2π=6.37 GHz (Q=25,000), g/2π=48 GHz (green dashed line) corresponds to the highest measured Q and the highest achievable g with this type of cavity and quantum dot. κ/2π=1.6 GHz, (Q=105), g/2π=48 GHz (blue dashed–dotted line) is for the highest achievable g in this system and a quality factor four times higher than what has been currently achieved in GaAs photonic crystals at this wavelength.