Fig. 3
From: High power surface emitting terahertz laser with hybrid second- and fourth-order Bragg gratings
Design considerations and comparison with a dual-slit second-order DFB structure. a Computed surface loss of the band-edge modes for the hybrid DFB structure shown in Fig. 2a, plotted as a function of d/Λ. Aperture spacing d is a design parameter that could be utilized to alter the respective losses and also the bandgap, which is also plotted. b Surface loss and bandgap is also plotted as a function of aperture spacing for a dual-slit second-order DFB structure (i.e., two slits are present in each grating period at the periodicity of Λ), which has been used for terahertz QCLs previously26. Electric field profiles near the center of cavities for both band-edge modes are plotted for the case of d/Λ = 0.4 as an example
