ENG-cladded metamaterial-loaded helical waveguide for optoelectronics applications

In this article, we have studied propagation characteristics of ENG-cladded metamaterial-loaded helical waveguide (CMLHG) to control its slow-wave behaviour for various engineering applications such as realizing optical buffer and memory. An analytical equation has been derived and computed numerically to analyse its dispersion characteristics in THz frequency spectrum. Significant amount of phase velocity reduction is achieved in comparison with the helical guide when (i) it is in free space and not cladded and (ii) when it is cladded with doubly positive materials and loaded with metamaterial. We find that helical waveguide physical dimensions, mainly radius and pitch angle, act as a tuning tool to control the phase velocity. This type of waveguide does not require any active waveguide compensation in order to achieve slow wave at THz to optical frequency range. The electric field intensity distribution over the cross section of the waveguide has also been studied which attributes that as frequency increases, electric field distribution is more confined to the core region of the waveguide.