Fig. 2: Lasing characteristics of individual CsPbBr3 microwire.
Optical images of luminescence signal below threshold (a), at threshold (b) and above threshold (c) under 400-nm fs excitation. Scale bars in a–c are 5 μm. d Emission spectra of CsPbBr3 microwires at different pump fluences. For clarity, the curves have been vertically shifted and some of them are magnified. e Integrated emission intensity (red circles) and full width at half maximum (FWHM, cyan squares) versus excitation energy density. The error bars that represent the standard deviation from the mean are too small to be visible. The representative kink behavior is exhibited and the lasing threshold is derived to be about 37.2 μJ cm−2. The spontaneous emission coupling factor β is estimated to be ~0.09 from the “S-shaped” curve. f Enlarged spectra with various excitation energy from 1.2 to 2.4 Pth. g The Q factors at various excitation fluences above the lasing threshold. The error bars here are too small to be visible. Inset is the lasing spectrum at a pump fluence of 72.3 μJ cm−2 with a emission peak at 543.8 nm and a FWHM (δλ) of about 0.23 nm, corresponding to a Q factor of ~2367.
