Photonic Wannier-Stark Ladder from Coupled Electromagnetic Cavities
(a) The peak frequencies in the three cases, periodic, small , and large . The vertical axis is in linear scale. (b) The same as (a) but with the vertical axis being logarithmic scale. The horizontal axis in (a) and (b) represents the peak number. The numbers, 3, 4, 5, 6, and 7, of the five peaks in the case of large are arbitrarily assigned, being not relevant to the line shape recognition. To see the linear line shape, a straight line connecting two end points is drawn, respectively, in (a) and (b).