Fig. 1. Shaping nondiffracting structured caustic beams. (a) Astroid; (b) deltoid; (c) cardioid; (d) pentagram caustics. (a1)–(d1) Caustic lines; (a2)–(d2) phase distributions; (a3)–(d3) ray pictures; (a4)–(d4) simulated transverse intensities of the astroid, deltoid, cardioid, and pentagram caustics, respectively.

Fig. 2. Theoretical simulations of astroid caustic with different q. (a) q = 0; (b) q = 5; (c) q = 10; (d) q = 15.

Fig. 3. Experimental system of generating caustic beams.

Fig. 4. Experimental recorded graphs of nondiffracting caustic beams with the same parameters as that in Fig. 1.

Fig. 5. Experimental recorded graphs of astroid caustic beams with the same parameters as that in Fig. 2.

Fig. 6. Astroid caustic beams at different propagation distances after the axicon. (a1)–(d1) Simulation intensity graphs; (a2)–(d2) experimental recorded intensity graphs. Propagation distances: (a1), (a2) z = 50 cm; (b1), (b2) z = 60 cm; (c1), (c2) z = 70 cm; (d1), (d2) z = 80 cm.

Table 1. Parametric Expressions for Different Curves