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," O