Experimental setup demonstrating entanglement between two photons. (a) The experimental setup: A 405 nm laser illuminates a β-barium borate (BBO) crystal to generate entangled photon pairs, with the idler photon in the upper arm and the signal photon in the lower arm. The metasurface (MS) encodes polarization information into holographic letters. (b) The signal photon’s hologram observed without a polarizer (eraser) in the idler arm. (c-f) Holograms with different polarizer orientations in the idler arm. The polarizer set to horizontal (H), diagonal (D), vertical (V), and antidiagonal (A) orientations selectively erases the corresponding letter in the holographic output. Credit: H. Liang et al., doi 10.1117/1.AP.7.2.026006

Quantum Holograms: Metasurfaces Unlock New Frontiers in Quantum Entanglement

Researchers have successfully created quantum holograms using metasurfaces, enabling unprecedented control over entangled photon pairs where the polarization of one photon can selectively erase holographic content in its partner, demonstrating precise quantum control with applications in secure communication and anti-counterfeiting technology.