Fig. 3: Q factors of the BIC modes with and without the flat-band multi-BIC design.
From: Ultracompact multibound-state-assisted flat-band lasers
a, Two-dimensional map of the Q-factor and polarization distributions of the flat-band with multi-BIC states in momentum space. The colour map represents the Q factor and the white dashed line represents the polarization vector. The topological charge was determined to be q = +2 by selecting a circle centred around the Γ point with |k| = 0.1(2π/√3/a) (Methods). b, Q-factor comparison of the flat-band cavities with and without the multi-BIC. The simulations here are conducted with periodic boundary conditions along the x–y axis (that is, infinite cavity sizes). c, Calculated Q factors for the fundamental mode of the flat-band cavities with and without the multi-BIC, along with the cavity with normal C6v-BIC. Here the calculations are based on realistic cavity structures with finite sizes, incorporating a double-metal device configuration with the consideration of the corresponding cavity losses. The solid lines are guides for the eyes.
