Fig. 1. A multilayer medium composed of N consecutive uniform dielectric layers

Fig. 2. The relationship between the material's refractive index and wavelength

Fig. 3. (a) Reflectance of DBR structures with different periods; (b) Reflection spectra of DBR structures with periods of 4, 6, and 8 over a broad wavelength range

Fig. 4. (a) The relationship between the thickness of the SiO₂ layer and the reflection bandwidth; (b) The relationship between the thickness of the ZnS layer and the reflection bandwidth

Fig. 5. Schematic diagram of the fabrication process for a broadband SiO₂/ZnS mirror-based VCSEL

Fig. 6. Reflection spectra of DBR structures deposited on different substrates. (a) Quartz glass; (b) GaAs

Fig. 7. SEM images of the SiO₂/ZnS DBR cross-section at different magnifications. (a) 5000 ×; (b) 20000 ×

Fig. 8. The microscope images of VCSEL devices with different oxidation apertures. (a) 6 μm; (b) 8 μm

Fig. 9. The P-I-V curves and spectra of VCSEL devices with different oxidation apertures. (a), (c) 6 μm; (b), (d) 8 μm

Fig. 10. Reflection spectra of DBR structures deposited on different substrates. (a), (b) 6 μm; (c), (d) 8 μm

Fig. 11. P-I-V and spectral characteristics of a DBR-based device with a 50 nm center wavelength shift. (a) P-I-V characteristics; (b) Spectral characteristics