Fig. 1. (a) Schematic of the epitaxial layer structure. (b) Formation of strain-induced warped microring. (c) Fabrication process of the warped microring.

Fig. 2. SEM images of (a) warped 40 μm microdisk and (b) warped 40 μm microring.

Fig. 3. PL spectra of (a) warped microdisk without a hole and (b) warped microring with an off-centered hole under different pumping power densities.

Fig. 4. FWHM and PL intensity of the warped microdisk without hole (red triangle) and with an off-centered hole (black square) along the excitation power density.

Fig. 5. (a) Relationship of PL intensity of the laser mode at 441.3 nm with the detection angle. The angle (φ) is defined in (b). (b) Illustration of warped microdisk in 3D spherical coordinate system. (c) CCD image of the warped microring. (d) Far-field pattern of the warped microring calculated by FDTD. The angle (θ) is defined in (b). Inset: top view of the simulation model.

Fig. 6. (a) Illustration of the simulation model with four individual planes placed at different heights on the warped microring. (b) Calculated electric fields distribution of the first-order WGM and higher-order WGM in the warped membrane, respectively. (c) Calculated resonance wavelength of the warped membrane.