Figure 2: Contour plots of signal gain (in dB) for an 8 mm long SRA in the plane formed by the factors and varying in the range 1 to 10. The location marked by + corresponds to the peak gain of 17.7 dB. Here, MW/cm2, MW/cm2, dB/cm, and ns. Other parameters are the same as in Figure 1. The red curve shows how the gain peak’s position drifts as changes from 15 MW/cm2 at point A to 300 MW/cm2 at point B .