Fig. 3: Laser behavior above the second threshold \({D}_{2}^{{{\rm{th}}}}\) near and away from an EP.
From: Dynamic gain and frequency comb formation in exceptional-point lasers
a The EP laser in Fig. 2a with Δ = 0, \({D}_{\max }=0.2\), σ/ε0 = 8.1 ps−1. b An ordinary AlGaAs laser cavity with DBR partial mirrors. c, d Spatial profiles E0 (red) and E1 (blue) at ω0 and ω1, from the full-wave PALT solution. The two profiles are orthogonal in the ordinary laser but almost identical in the EP laser. e, f Dynamics of the population inversion D(x0, t) and electrical field E(x0, t) at the location x0 shown in (a, b). 〈D〉t denotes the inversion averaged over time. g, h The intensity spectrum, comparing the PALT solution to the existing “steady-state ab initio laser theory” (SALT) and to FDTD simulations of the Maxwell–Bloch equations.
