Efficient light-trapping sheet for the entire visible spectrum by using stacked concentric grating couplers

Abstract

We confirmed the effectiveness of light-trapping by forming concentric grating couplers (CGCs) inside a transparent sheet. A portion of the light incident to the CGCs is input-coupled and converted to the guided mode and is radiated from neighboring CGCs at a wider angle than the incident angle or even over the critical angle for both surfaces of the sheet. We demonstrated that three stacked sheets with multi-layered CGCs can trap an average of 19%–29% of the incident light at angles of 0° to ±70° in the visible spectrum.

Real-Time Imaging of Plasmonic Concentric Circular Gratings Fabricated by Lens–Axicon Laser Interference Lithography

“…Concentric circular gratings stand out as particularly intriguing due to their unique radial surface features, which make them highly desirable in applications such as alignment marks in lithography techniques [10], distributed feedback lasers [11,12], light-trapping elements in luminescent enhancing applications [13][14][15], plasmonic solar cells [16,17] and for the generation of radially and azimuthally polarized light using plasmonics [18,19].…”