Fig. 3: LIGHTNING in action in solutions of RSFPs.

Normalized absorption (a) and emission (b; excitation at λ₁ = 488 nm) spectra of 5 μM solutions of the RSFPs 1–22 in pH 7.4 PBS buffer with linear grey scale between 0 and 1; c Heatmap displaying the deviations from the mean value \(\overline{\tau }\) over the RSFPs of the characteristic times measured in 10 μM solutions over the [1 μs–1 s] time window for each illumination in decimal logarithmic scale; d LIGHTNING discrimination in RSFP solutions in the 4D space of characteristic times. The volume associated with each RSFP is fixed by the resolution limit. I_low (I₁ = 2), II_low (I₁ = 0.1, I₂ = 0.1), I_high (I₁ = 200), and II_high (I₁ = 2 and I₂ = 90) with I₁ and I₂ in ein m⁻² s⁻¹. T = 298 K.