  The electronic and optical properties of nonuniform bilayer graphene
nanoribbons are worth investigating as they exhibit rich magnetic quantization.
Based on our numerical results, their electronic and optical properties
strongly depend on the competition between magnetic quantization, lateral
confinement, and stacking configuration. The results of our calculations lead
to four categories of magneto-electronic energy spectra, namely monolayer-like,
bilayer-like, coexistent, and irregular quasi-Landau-level like. Various types
of spectra described in this paper are mainly characterized by unusual spatial
distributions of wave functions in the system under study. In our paper, we
demonstrate that these unusual quantized modes lead to the appearance of such
diverse magneto-optical spectra. Moreover, the investigation of the density of
states in our model leads to the appearance of many prominent symmetric and
weakly asymmetric peaks. The almost well-behaved quasi-Landau levels exhibit
high-intensity peaks with specific selection rules, and the distorted energy
subbands present numerous low-intensity peaks without any selection rules.
