Figure 3
From: Bending light via adiabatic optical transition in longitudinally modulated photonic lattices
(a) Spectra of β as a function of longitudinal modulation period T. The FB modes in bands indexed by n = 1 and n = 3 are indicated by the red and blue bold solid curves, respectively. The thin straight lines show the spectra of β for corresponding lattices without longitudinal modulation. The dashed vertical line indicates the position of resonant longitudinal period T0 where adiabatic optical transition between FB modes from different bands occurs. (b) Beam propagation trajectory of a wide Gaussian beam in lattice with adiabatically decreasing longitudinal modulation period T. The yellow dashed line corresponds to the resonant longitudinal modulation period T0. The red arrow indicates the incident beam at λ = 0.6328 μm with a transverse wave vector kx = 0.7π/D. The other lattice parameters are D = 10 μm, δn = 5 × 10−4 and n0 = 2.3, respectively.
