Theoretical large positive and negative lateral beam shift of the metal cladding waveguide in the mid-infrared region

A large negative and positive lateral beam shift is presented in the midinfrared region based on the penetration enhancement effect of the ultrahigh order modes in the metal-cladding waveguide. The characteristics of the lateral beam shift have been discussed in theory, and the performance of the ultrahigh order modes is confirmed in an experiment at 5.4 µm. The negative and positive lateral shift depends on the derivative of the imaginary part of the propagation constant.