Fig. 6: Functionalities of the flexible and rollable HMM device.

a The emission spectra of random lasing action for the HMM2 device with increasing cycle index at the pumping energy density of 0.24 kW cm⁻². The photo image of the rollable HMM assisted by a wood stick with a diameter of 1 mm (yellow color) b under rolling and c flattening. Scale bars represent 3 mm. d The emission intensities of random lasing action of repeated rolling-flattening processes up to 50 times under the pumping energy density of 0.24, 0.20, and 0.13 kW cm⁻². The solid straight line is the fitted results for the rolling state and the dash straight line is for the flattening state. e The emission intensities measured from normal to tilted sample holder of 60° under the pumping energy density of 0.24 and 0.31 kW cm⁻². Inset is the schematic diagram of the measuring process for the tilted sample holder. f The lasing spectra with laser expose of PNCs on HMM2 substrate for continuously 60 min at the pumping energy density of 0.24 kW cm⁻².