Pattern Revivals from Fractional Gouy Phases in Structured Light

We investigate pattern revivals in specially designed optical structures that combine different transverse modes. In general, the resulting pattern is not preserved under free propagation and gets transformed due to nonsynchronized Gouy phases. However, it is possible to build structures in which the Gouy phases synchronize at specific fractional values, thus recovering the initial pattern at the corresponding longitudinal positions. This effect is illustrated with a radially structured light spot in which the beam energy can be addressed to different positions without the need of intermediate optical components, which can be useful for optical communications and optical tweezing with structured beams.

Figure 1

Experimental setup.

Figure 2

Measured (top) and calculated (bottom) intensity distribution of the structure given by Eq. (19) at different planes along propagation.

Figure 3

Propagation sequence of the structured spot pattern forming the initials UFF. Three propagation planes are displayed: $z=0$ (top), 53 mm (middle), and 117 mm (bottom). A revival is evident at 117 mm.

Figure 4

3D plot of the intensity distribution along a beam diameter at different propagation planes for the structured spot given by Eq. (20). The experimental result is displayed at the top graph and the theoretical calculation is shown at the bottom. Two revivals can be clearly seen, the first one located at 3.55 mm and the second one at 8.00 mm.

Figure 5

Experimental results for the long range revival of the structured spot given by Eq. (21). The first revival occurs around 3.09 m from the initial plane.