Fig. 2: Metallic THz PEPC lattice design and simulation.
From: High brightness terahertz quantum cascade laser with near-diffraction-limited Gaussian beam
a Schematic of the supercells of the THz PEPC lattice consisting of an elliptical hole (long half axis a1 = 0.24a, short half axis b1 = 0.12a) and a circular hole (radius r = 0.12a) with a phase shift d in both x and y directions. b Calculated photonic band structures of the THz PEPC for TM polarization around the Γ2 point. c Schematic of the reciprocal lattice of PEPC and its in-plane coupling diagram. d Calculated in-plane 1D and 2D coupling coefficients as a function of the phase shift d between the two lattices. e Electric field (|Ez|2) distribution of the fundamental and first high-order modes of the THz PEPC QCL. f Modal loss margin between the fundamental and first high-order modes in the PEPC resonator as a function of phase shift. The inset shows the high-order mode profile involving with the phase shift. The dashed line indicates the modal loss margin of a PC cavity with similar lattice parameters. The shaded area indicates the phase shift region where the in-plane 1D coupling strength is insufficient for the given device area
