Fig. 5

The spectra of the overall output coefficient \(\Theta\) and transmissivity T of the 1D TMPTSPROWN with a single unit cell optimized by the first-three extremum spontaneous PT-symmetric breaking points. The red and blue solid curves indicate the results of \(\Theta\) and T, respectively. (a) The first extremum breaking point. (b) The second extremum breaking point. (c) The third extremum breaking point.