Figure 3

From: The influence of whispering gallery modes on the far field of ring lasers

Figure 3

(a) Sketch of two continuous phase shifts. The black circles represent the locations of strongest light annihilation. (b) Slit width and calculated surface losses as a function of the etch depth. Small grating slits exhibit a reduced etch depth and therefore a weaker light emission. (c) Calculated electric near field amplitude ENF of a continuous π-shift (solid black) and reference amplitude (dashed black) along the ring. The horizontal (dotted magenta) and vertical (dotted green) polarization components are given by the product of ENF with a cosine and sine function, respectively. The faint kinks at 0° ± 19° and 180° ± 19° originate from the onset of the dual grating region. The dotted blue line represents the near field amplitude of an abrupt π-phase shift. Near field intensity pattern of an abrupt (d) and a continuous (e) π-phase shift ring QCL.