Single nanowire lasers based on bottom-up III-V materials have been shown to exhibit room-temperature near-infrared lasing, making them highly promising for use as nanoscale, silicon-integrable, and coherent light sources. While lasing behavior is reproducible, small variations in growth conditions across a substrate arising from the use of bottom-up growth techniques can introduce interwire disorder, either through geometric or material inhomogeneity. Nanolasers critically depend on both high material quality and tight dimensional tolerances, and as such, lasing threshold is both sensitive to and a sensitive probe of such inhomogeneity. We present an all-optical characterization technique coupled to statistical analysis to correlate geometrical and material parameters with lasing threshold. For these multiple-quantum-well nanolasers, it is found that low threshold is closely linked to longer lasing wavelength caused by losses in the core, providing a route to optimized future low-threshold devices. A best-in-group room temperature lasing threshold of ∼43 μJ cm under pulsed excitation was found, and overall device yields in excess of 50% are measured, demonstrating a promising future for the nanolaser architecture.

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The modulation of the required light wavefront polarization and phase based on the geometric phase encoding metasurface (GPEM) has recently become a hot topic. However, the transmission coefficient of a geometric phase metasurface is greatly decreased when the structure is rotated. To address this problem, a solution of adding a tapered antireflection layer to the substrate and design an all‐dielectric encoding metasurface composed of titanium dioxide and silicon dioxide in the visible light band with a transmission coefficient of 93.65%, is proposed. When circularly polarized light is incident on the designed encoding metasurfaces with rotating unit structures, the GPEM still maintain almost perfect transmission coefficient as with initial linearly polarized light is incident. By comparing the coded metasurface with and without conical structure, the coded metasurface with conical structure can greatly improve transmission efficiency. Importantly, the Fourier convolution theorem in digital signal processing is introduced on encoding metasurfaces. The scattering angle of transmission can be controlled arbitrarily by the all‐dielectric coded metasurface with Fourier convolution addition and subtraction operations.

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