fig8

Figure 8. Top-view SEM image of (A) the pristine MAPbI₃ perovskite layer and (B) the 2D-PC. (C) Emission spectra upon optical pumping with increasing energy density 1.6-4.7 µJ cm^-2. (D) Tunability of the laser emission upon variation of the excitation spot on the sample. (A-D) is quoted with permission from Pourdavoud et al.^[120]. (E) Schematic of the DFB laser with the assignment of directions and a sketch of the laser emission as a result of first-order diffraction normal to the sample surface. (F) SEM images of the DFB grating imprinted into the MAPbBr₃ layer. (G) Emission spectra upon optical pumping with increasing energy density 0.5-5 µJ cm^-2. (H) Emission spectrum of the laser measured with high spectral resolution. (E-H) is quoted with permission from Pourdavoud et al.^[121].