Fig. 5: Temporal radiative-loss tuning around the RSP-BIC condition.
From: Optical control of resonances in temporally symmetry-broken metasurfaces
a, Illustration of the SP-BIC mode around the RSP-BIC condition for an l2 sweep before (grey) and after (blue) pumping of the structure. b–e, Four key positions are highlighted with grey cuts where resonances are broadened (b), created (c), annihilated (d) or sharpened (e), all dependent on the initial ratio of p1 to p2. b, Transmittance time evolution with a 100 μJ cm−2 pump pulse at 720 nm of the gradient position with l2 = 236 nm, where p1 < p2, showing an increase in resonance amplitude and the radiative loss γrad. c, Time evolution with l2 = 226 nm, where p1 = p2 for the initial structure. After pumping, a mode is created, which quickly decays after 10 ps. This is also reflected in the γrad fit, which increases from 0 to 0.058 THz before exponentially decaying. The fit is restricted to the time interval where the resonant mode is visible. d, Time evolution with l2 = 210 nm, where p1 > p2, showing the annihilation of the BIC mode, which reappears after approximately 20 ps. e, Time evolution with l2 = 186 nm, where p1 > p2, resulting in a decrease of γrad and sharpening of the mode. Insets in b–e are the transmittance spectra at t = 0 and 1 ps. Scale bar, 100 nm (b).
