Fig. 1. (a) Structure diagram of centrifugal microfluidic chip. (b) Schematic fabrication process of PCLC microdisk.

Fig. 2. (a)–(c) Distribution of dye-doped PCLC microdisks in each ring channel of centrifugal microfluidic chip and (d) the diameters of microdisks in the main channels for type I samples collected from droplets with diameters of 92 μm, 136 μm, and 180 μm. (e) Simplified physical model to analyze the broken microdisks in the outermost ring channels. (f) Microscopic images of 180 μm droplet and corresponding microdisks in the fourth, fifth, and sixth ring channels. The scale bar is 100 μm.

Fig. 3. Lasing properties of dye-doped PCLC microdisk samples of type I collected from 180 μm droplets. (a) Reflectance spectra of samples in three main channels and the fluorescence spectrum of DCM. (b) The laser emission spectra with a fixed pump energy of ∼5μJ/cm2 and (c) lasing thresholds of samples in three main channels. (d) The temperature-dependent laser emission spectra of samples in the fifth ring channel.

Fig. 4. (a) Reflection spectra and (b) microscopic images in reflection mode in four consecutive stages (before curing, after curing, after washing out, and after refilling) for dye-doped PCLC microdisk samples of type II in the fifth ring channel collected from 180 μm droplets. The inset in (a) shows SEM images of the PCLC microdisk after washing out with the scale bars of (I) 50 μm and (II) 0.2 μm; the scale bar of (b) is 50 μm.

Fig. 5. Lasing properties of dye-doped PCLC microdisk samples of type II in the fifth ring channel collected from 180 μm droplets. (a) Reflectance spectra of samples at various temperatures and the fluorescence spectrum of DCM. (b) Temperature-dependent laser emission spectra at a fixed position with a fixed pump energy of ∼5μJ/cm2 and (c) lasing thresholds of samples. (d) Potential applications in optical barcodes.