Subwavelength photonic hook generated by shaped fiber tip with asymmetric terahertz radiation

We demonstrate the concept of fiber-based terahertz hook. The subwavelength photonic hook is obtained in the vicinity of a shaped fiber tip with asymmetric radiation. A 193 THz continuous-wave source, commonly used for medical imaging, has been required. Photonic hook with a lateral feature size less than the half-wavelength is achieved using a hemispherical shaped fiber tip with metallic mask. This breakthrough is carried out in ambient air by using a 2.58λ - diameter fiber with a shaped tip (λ is a radiation wavelength). A good correlation is observed between the computed intensity distribution of photonic hook and the tip sizes. Photonic hook generated with a shaped fiber tip, easier to manipulate, shows far-reaching benefits for potential applications such as ophthalmic laser surgery, super-resolution microscopy, photolithography, and material processing.