The development of novel approaches that control absorption and emission operating in long wavelength infrared (LWIR) spectral region is of fundamental importance for many applications, such as, remote temperature sensing, environmental monitoring, thermal imaging, radiation cooling and industrial facility inspections. A high performance plasmonic metasurface-based absorber for the LWIR spectral region is presented. In our design, a pyroelectric thin film, poly(vinylidene fluoridetrifluoroethylene) (P(VDF-TrFE)) copolymer, is introduced as spacer, that offers the device not only with multiple selective high absorption bands but also promising potential for application in optoelectronics. By employing a scattering-type near-field optical microscopy (s-SNOM), both the near-field amplitude and phase optical responses of the absorber are investigated at resonant wavelength, thereby providing direct experimental evidence to verify the nature of the absorption effect. To further demonstrate the versatility of our design, a particular metasurface patterned by the building blocks of the plasmonic absorber is fabricated and characterized. Two-dimensional hyperspectral images show that such a patterned structure exhibits both frequency and spatially selective absorption.

In this work, the authors propose and experimentally demonstrate a large-area long-wavelength infrared thermal emitter, which is spectrally selective, highly directional, and easily fabricated.

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AbstractWide gamut and angle-insensitive structural colors are highly desirable for many applications. Herein, a new type of lithography-free, planar bilayer nanostructures for generating structural colors is presented, which is basically composed of a deep-subwavelength, highly absorbing dielectric layer on an opaque metallic substrate. Experimental results show that a galaxy of brilliant structural colors can be generated by our structures, and which can cover ∼50% of the standard red–green–blue color space by adjusting the nanostructure dimensions. The color appearances are robust with respect to the angle of vision. Theoretical partial reflected wave analyses reveal that the structural color effect is attributed to the strong optical asymmetric Fabry–Perot-type (F–P-type) thin-film resonance interference. The versatility of the structural color properties as well as the simplicity of their fabrication processes make this bilayer structures very promising for various applications, such as security marking, information encryption, and color display, etc.