a Two-step irradiation to pattern right-handed and left-handed PDA sequentially on a film. b Either right- or left-circularly polarized fluorescence emitted with high asymmetry factors (glum = ±0.1 at ~605 nm). c A matrix of PDA patches with tailorable chirality. The patches in each row are irradiated with varying amounts of 254 nm and in each column with varying amounts of 313 nm, resulting in a 2D matrix of PDA patches each with its own unique combination of chirality and intensity. For example, right-handed PDA is found in the northeast corner, left-handed PDA in the southwest corner, and achiral PDA in the diagonal patches; while chirality varies along the diagonal direction of northeast-southwest, the intensity of fluorescence increases step-wisely along the other diagonal from northwest to southeast. At least three experiments were performed to obtain the average signals, and error bars represented standard deviations of measured signals.