Realization of a helix-based perfect absorber for IR spectral range using the direct laser write technique

We report the design and fabrication of perfect absorber metasurfaces for infrared spectral range using the direct laser writing technique. The metasurface structures have a helix-based architecture, which has advantages in comparison to traditional planar architectures, but is difficult to fabricate due to complex shapes and the sub-micrometer size of 3D helices comprising them. This challenge was addressed by fabricating dielectric templates of structures using the femtosecond direct laser write technique, which provides spatial resolution close to 100 nm, and subsequently metalizes the templates using gold sputtering. Optical characterization of the fabricated samples reveals resonant absorption in excess of 80% in the wavelength range of 6 - 11 mu m in accordance with theoretical expectations. Similar structures may find applications in bolometers, narrow-band thermal detectors and emitters, and infrared energy harvesting devices. (C) 2017 Optical Society of America