Fig. 2
From: Statistical parity-time-symmetric lasing in an optical fibre network
Comparison of the thresholds from a PT-symmetric cavity and a reference cavity. The threshold-reduction factor \(\eta = {G_{{\rm{Ref}}}}/{G_{{\rm{PT}}}}\), where G Ref and G PT are the lasing thresholds for the reference gain-only cavity and the PT-symmetric cavity configurations, respectively, shown schematically at the top. We plot η with R and R 2, and two colour palettes are used to distinguish the regime of PT-enhanced threshold where introducing the gain-balancing loss reduces the lasing threshold with respect to that of the reference gain-only cavity (η>1, red palette), and PT-diminished threshold (η<1, blue palette), delineated by a black curve (η=1). The horizontal green line corresponds to the experimental value R=0.82, and the circles to the experimental values of R 2 (see Table 1)
