Terahertz radiation has strong potential for applications in biomedical sensing, noninvasive imaging, and spectroscopy. But terahertz sources are generally bulky, so designing efficient waveguides that can collect and deliver terahertz radiation remotely is a priority. Scientists at the Ecole Polytechnique (Montreal, QC, Canada) have proposed a porous polymer fiber for transmitting terahertz radiation. Because many materials highly absorb terahertz radiation, the group designed a fiber core with a hexagonal array of subwavelength air holes to maximize the fraction of power guided in air.
Numerical simulations by Alireza Hassani and colleagues confirmed that the majority of the guided power propagates inside the microstructured air holes within the core, resulting in less radiation absorbed by the core material, and thereby improving transmission efficiency. The fiber achieves low modal transmission loss with a typical bulk absorption loss-suppression factor of 10 to 20. As a result, even in the presence of tight bends of 3 cm radii, modal radiation loss is comparable to modal absorption loss, making the fiber highly tolerant to bending and enabling more practical fiber-coupled terahertz components and systems. Contact Maksim Skorobogatiy at [email protected].