Axicon metalens for broadband light harvesting

Abstract

In this study, an axicon metalens comprising a large central disc surrounded by nanoposts for energy harvesting in composite metal-oxide semiconductor sensors was designed, fabricated, and experimentally characterized. The main role of the central disc is focusing light; the nanoposts of various diameters deflect light to form a Bessel-like beam. The spatial distribution of the optical transmission was measured using micro-hyperspectral imaging. The axicon metalens concentrates the light to the sensitive area of the sensor and also harvests light from adjacent pixels. After adding an axicon metalens, the normalized peak transmission is up to 250% at λ = 700 nm as compared to a blank TiO2 film. The experimental results had fair agreement with the finite-difference-time-domain simulation. The ultra-broadband energy-harvesting performance of the sensor suggests that it could be applied in surveillance and Internet of Things applications.

High-Efficiency Integrated Color Routers by Simple Identical Nanostructures for Visible and Near-Infrared Wavelengths

“…Hence, the color router is polarization-insensitive, providing a much simpler construction and improved efficiency for visible and NIR imaging. As shown in Table 3, compared to previously reported metasurface-based color routers, our new design employs a much simpler nanostructure for fabrication by electron beam lithography and dry etching [19][20][21][22]25,28]. Our design method is versatile and can be applied when modifying the pixel size of the imaging sensor.…”

“…The Metasurface-based color routers can orient the light rather than filtering it, which effectively increases the imaging efficiency [18][19][20][21][22][23][24][25][26]. However, the previously reported color metasurface-based routers suffer from having complicated structures, posing high accuracy requirement for their fabrication [19][20][21][22][23][24][25][26][27][28].…”

High-Resolution Metalens Imaging with Sequential Artificial Intelligence Models

“…To verify the imaging performance of the metalens in question, a characterization was carried out to analyze the transmittance distributions at the air/GaN interface throughout the metalens using an HSI microscope. 36 The HSI microscope (see Supplementary Section 2) allows for the detailed analysis of the optical properties across the metalens, providing valuable insights into its optical behavior and performance. Figure 3a presents the transmittance of metalens, which has been collected and averaged by the metalens' area.…”