A hemispherical surface structure was fabricated on a sapphire substrate by utilizing a self-assembly and spin-coating process for a terahertz (THz) antireflection coating. The self-assembled glass spheres and spin-coated material led to a gradual change in the effective refractive index. The aspect ratio of the hemispherical surface structure was controlled easily by adjusting the thickness of the B-staged bisbenzocyclobutene used as a coating. The reflectance of the fabricated hemispherical surface structure, having a period of 140 μm, exhibited low reflectance and low Fabry–Perot resonance in a THz spectral range from 0.1 to 1.9 THz.
© 2012 Optical Society of America
Original Manuscript: January 30, 2012
Revised Manuscript: May 16, 2012
Manuscript Accepted: May 21, 2012
Published: June 28, 2012
Dae-Seon Kim, Dong-Ju Kim, Dong-Hyun Kim, Sehyun Hwang, and Jae-Hyung Jang, "Simple fabrication of an antireflective hemispherical surface structure using a self-assembly method for the terahertz frequency range," Opt. Lett. 37, 2742-2744 (2012)