Fig. 1. (a) Simulation model of blue microdisk laser diode; (b) Real part of the refractive index; (c) Imaginary part of the refractive index of a Lorentz material

Fig. 2. (a) Side view of QWs；(b) Top view for one QW (The Lorentz gain material and no gain material are set in the red and blue region in figure (b))

Fig. 3. (a) The FDTD simulation resonance of devices with different diameter for the inner circle (The inset figure: a schematic of the gain setting. The Lorentz gain material and no gain material are set in the red and blue region in figure (a)); The XY-cross section electrical field intensity distributions at (b) 404.871 nm, (c) 413.9 nm, (d) 424.468 nm, (e) 438.462 nm and (f) 448.315 nm

Fig. 4. The total output power as a function of diameter of inner circle

Fig. 5. The FDTD simulation resonances of devices with 0.4 μm diameter inner circle and different offset (The inset figure: a schematic of the gain setting. The Lorentz gain material and no gain material are set in the red and blue region)

Fig. 6. The normalized peak power of the five modes as a function of the offset of the inner circle

Fig. 7. Optical resonances for devices with different no-gain outer ring (The inset figure: a schematic diagram of the gain setting. The Lorentz gain material and no gain material are set in the red and blue region)

Fig. 8. Normalized peak power of the five modes as a function of the width of no-gain outer ring