Low-cost antireflection coatings for terahertz light employing multilayered polymer films and adhesives

Antireflection coatings (ARCs) provide a powerful method to reduce reflective losses and eliminate spurious reflections that can limit experiments. At Terahertz (THz) frequencies, ARC options remain limited. To address this, we employ a combination of commercially available polymer adhesive tapes and films to create ARCs for THz light, that can be applied on a wide range of substrates. In addition to their ease of application, one coating can be removed from a substrate and a different one can be applied. Both narrow and wide band performance are achieved from different coatings, which can be tuned to a target frequency by altering the thickness of polymer layers. We have experimentally evaluated the efficacy of the layered structures in the bandwidth 0.25-2.25 THz using THz time domain spectroscopy. Taking the optical properties of each layer into account, we can model the response of ARCs in both frequency and time domains. These economic coatings can have vast applications where the attenuation of Fresnel loss or Fabry-Perot effect is desired.