Figure 3 | Scientific Reports

Figure 3

From: Vortex Laser based on III-V semiconductor metasurface: direct generation of coherent Laguerre-Gauss modes carrying controlled orbital angular momentum

Figure 3

(a1) Schematic description of the vortex semiconductor-laser, based on III-V semiconductor technology. Stable cavity with a millimetre air gap Lc. Pump diameter 90 μm. (a2) SPM and intensity filter (loss masks). (a3) Elementary cell of the 2D sub-wavelength grating forming the metasurface. (a4) Perturbative azimuthal phase distribution ΔϕSPM induced by the SPM. (b1) Scanning electron microscope image of fabricated right-handed SPM surrounded by a Chromium metallic mask. (b2) Zoom on SPM (20 μm external diameter). (c1) Longitudinal E-field distribution in the 1/2 VCSEL structure and SPM position. (c2) Longitudinal (XZ) cross section showing the overlap of the LG00 and LG01 modes with the SPM and the intensity filter, the peak of unwanted LG00 mode coincides with the high central loss.

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