Gradient Index Porous Core Photonic Crystal Fiber for Sub-wavelength Field Confinement

A porous core gradient index photonic crystal fiber (PCF) has been designed to achieve enhanced field localization in the terahertz (THz) regime. The proposed gradient index profile ensures stronger electromagnetic field localization from 0.15THz to 0.2THz compared to the conventional PCF. The quality factor determined for the PCF without gradient index profile is 2.4598×10
⁸
with 84.04% of power propagating along the core. In contrast, the quality factor of the PCF with gradient index profile turns out to be 2.2849×10
⁹
with 99.69% of power propagating along the core. This clearly explains the sub-wavelength confinement of the enhanced field localized owing to the employed triangular gradient index profile.