Fig. 1. Diagram of femtosecond laser two-photon fabrication system

Fig. 2. Diagrams of shape changes of Janus micropillar. (a) Machining process of Janus micropillar; (b) micropillar after machining; (c) micropillar in straight state; (d) micropillar in bending state

Fig. 3. Optical micrographs of highly controllable Janus micropillars. (a) Janus micropillar arrays composed of three micropillars; (b) Janus micropillar arrays composed of four inward micropillars; (c) Janus micropillar arrays composed of four outward micropillars

Fig. 4. Applications of Janus micropillars in encryption and decryption of information. (a) Conceptional design of encryption (left) and decryption (right); (b) optical micrographs of encryption (left) and decryption (right) of J