Figure 2.

Switching cycles of fulgimide 1 when operated as a D flip-flop. The fluorescence output (λ_exc = 550 nm, λ_em = 644 nm) with associated noise is shown for 10 cycles. One cycle consists of the following action sequence: (1) irradiation with 1064 nm IR light; (2) simultaneous irradiation with 532 nm light and 1064 nm light via a THG (effectively corresponding to 355 nm light); (3) irradiation with 1064 nm IR light; (4) irradiation with 532 nm light. Each irradiation step was performed for the constant time of 45 s, and the fluorescence output was monitored for 5 s. The dashed line represents the threshold level used to distinguish output = 1 from output = 0.