Fig. 3

Full-color tunable lasing. a Lasing spectra and corresponding photoluminescence images when different positions of the RGB pixel were pumped above their thresholds. From top to bottom: the blue (B), green (G), red (R), blue and green (B + G), blue and red (B + R), green and red (G + R), and blue, green and red (B + G + R) emissive spherical caps. The numbers show the CIE1931 coordinates calculated from the corresponding spectra. All scale bars are 20 μm. b Chromaticity of the lasing peaks extracted from the spectra in a, shown as seven white circles. The dashed lines indicate the range of the achievable color gamut for the RGB pixel. c Far-field photograph of the “ICCAS” patterns of pixel arrays comprising different RGB emissive spherical caps. Mixed far-field emission colors of blue, green, red, cyan, magenta, yellow, and white were clearly observed from the panel under UV excitation. The scale bar is 2 mm