The bright and iridescent blue color fromMorphobutterfly wings has attracted worldwide attentions to explore its mysterious nature for long time. Although the physics of structural color by the nanophotonic structures built on the wing scales has been well established, replications of the wing structure by standard top-down lithography still remains a challenge. This paper reports a technical breakthrough to mimic the blue color ofMorphobutterfly wings, by developing a novel nanofabrication process, based on electron beam lithography combined with alternate PMMA/LOR development/dissolution, for photonic structures with aligned lamellae multilayers in colorless polymers. The relationship between the coloration and geometric dimensions as well as shapes is systematically analyzed by solving Maxwell’s Equations with a finite domain time difference simulator. Careful characterization of the mimicked blue by spectral measurements under both normal and oblique angles are carried out. Structural color in blue reflected by the fabricated wing scales, is demonstrated and further extended to green as an application exercise of the new technique. The effects of the regularity in the replicas on coloration are analyzed. In principle, this approach establishes a starting point for mimicking structural colors beyond the blue inMorphobutterfly wings.
We present transmissive plasmonic structural colors from subwavelength nanohole arrays with bottom metal disks for scaled-up manufacturing by nanoimprint lithography (NIL). Comprehensive theoretical and experimental studies are carried out to understand the specific extraordinary optical transmission behavior of the structures with such bottom metal disks. Distinctive colors covering the entire visible spectrum can be generated by changing the structural dimensions of hole arrays in Ag covered by the metal disks. The plasmonic energy hybridization theory is applied to explain the unstable color output with shallow holes so that a large processing window during NIL could be achieved for mass production. A high-resolution of 127,000 dots per inch is demonstrated with potential applications, including color filters and displays, high-resolution color printing, CMOS color imaging, and anti-counterfeiting.
Polarimetric imaging enhances the ability to distinguish objects from a bright background by detecting their particular polarization status, which offers another degree of freedom in infrared remote sensing. However, to scale up by monolithically integrating grating-based polarizers onto a focal plane array (FPA) of infrared detectors, fundamental technical obstacles must be overcome, including reductions of the extinction ratio by the misalignment between the polarizer and the detector, grating line width fluctuations, the line edge roughness, etc. This paper reports the authors’ latest achievements in overcoming those problems by solving key technical issues regarding the integration of large-scale polarizers onto the chips of FPAs with individual indium gallium arsenide/indium phosphide (InGaAs/InP) sensors as the basic building blocks. Polarimetric and photovoltaic chips with divisions of the focal plane of 540 × 4 pixels and 320 × 256 superpixels have been successfully manufactured. Polarimetric imaging with enhanced contrast has been demonstrated. The progress made in this work has opened up a broad avenue toward industrialization of high quality polarimetric imaging in infrared wavelengths.