Fig. 1. Schematic representation of the beam mixing process in transmission plate.

Fig. 2. Samples of equivalent phases and the corresponding AM patterns of SSD beam induced by etalon effect. In the left three figures, red curves and blue curves denote the equivalent phase and the original phase, respectively. The parameters are (a) one sinusoidal phase modulation with $\unicode[STIX]{x1D711}_{0}=2\unicode[STIX]{x1D70B}n_{0}$, $a=2$, (c) one sinusoidal phase modulation with $\unicode[STIX]{x1D711}_{0}=2\unicode[STIX]{x1D70B}n_{0}+\unicode[STIX]{x1D70B}/3$, $a=3.5$ and (e) two sinusoidal phase modulations with $\unicode[STIX]{x1D711}_{0}=2\unicode[STIX]{x1D70B}n_{0}+\unicode[STIX]{x1D70B}/3$, $a_{1}=3$, $a_{2}=2$. The corresponding temporal ripples are shown in (b), (d) and (f) and the intensity scale is normalized to mean intensity.

Fig. 3. Schematic representations of the focusing process for an SSD beam (single sinusoidal phase modulation). Integration of intensity on focal plane can reduce the distortion criterion of SSD beam. The colors represent the isointensity surface in near field, and the horizontal dashed line corresponds to AM patterns in near field as shown in Figure 2.

Fig. 4. (a) Dependence of the far-field distortion criterion on the number of color cycle for an SSD beam, where the equivalent phase of $\unicode[STIX]{x1D711}_{0}$ is 0, $\unicode[STIX]{x1D70B}/6$, $\unicode[STIX]{x1D70B}/3$ and $\unicode[STIX]{x1D70B}/2$, respectively. (b) The comparison of AM patterns in near field and far field for an SSD beam with the parameters $N_{c}=1.3$ and $\unicode[STIX]{x1D711}_{0}=2\unicode[STIX]{x1D70B}n_{0}+\unicode[STIX]{x1D70B}/3$.