Fig. 1. Schematics of the triple-lattice PCSELs. (a) Cross-sectional schematic of the PCSELs. (b) Schematic of the coupled waves in the photonic-crystal resonator. (c) Total radiation loss of the PCSELs as a function of cavity size for various photonic-crystal resonators. The inset is a schematic of the unit cell of a triple-lattice photonic crystal.

Fig. 2. Microscope images of the fabricated triple-lattice PCSELs. (a) Optical micrograph of the laser chip bounded to a thermally conductive submount with p-side down. The left-bottom inset shows the structure of the epi-side. (b) Top-view SEM image of the photonic crystal. (c) Cross-sectional SEM image of the embedded photonic crystal.

Fig. 3. Measured light-current characteristics of the triple-lattice PCSELs. (a) Temperature-dependent light-current curves of the PCSELs. (b) Threshold current as a function of operating temperature.

Fig. 4. Lasing spectra of the triple-lattice PCSELs. (a) Measured room-temperature lasing spectra at various injection currents under CW conditions. (b) Calculated radiation loss of the eigenmodes as a function of wavelength. (c) Temperature dependence of the lasing spectra at an injection current of 80 mA.

Fig. 5. Measured emission patterns of the PCSELs under room temperature. (a) Near-field patterns at 33 mA (below I_th), 39 mA (above I_th), and 80 mA (far above I_th). The dashed white circle indicates the output aperture. (b) Far-field patterns at 39 and 80 mA. (c) Far-field profiles at 80 mA.

Fig. 6. Frequency response of the triple-lattice PCSELs. (a) Photograph of the experimental setup. (b) Measured scattering parameter (S12) versus frequency dependency for various drive currents.

Fig. 7. Influence of mesa sizes and lattice separation. (a) Light-current curves of the PCSELs with various mesa sizes D. (b) The contrast of threshold current and slope efficiency of the PCSELs. (c) Light-current curves of the PCSELs with various lattice separations d. The right insets show the top-view SEM images of the photonic crystal before regrowth.