Quantum imaging

Quantum entanglement

Physics

Nonlinear system

Quantum technology

Optics

Quantum network

Open quantum system

Photon

Quantum information

Spontaneous parametric down-conversion

Quantum mechanics

Optoelectronics

Quantum optics

Quantum

Quantum sensor

Science

Metalens-array–based quantum source Spontaneous down-conversion is an exotic optical process in a nonlinear crystal in which a high-energy photon splits into two lower-energy photons that are quantum mechanically entangled. These entangled pairs are valuable commodities for quantum information processing and quantum communications. Because the experimental setup is usually performed with bulk optical components, there is a need to decrease the size scale for application. Li et al. combined an array of specialized metalenses with a nonlinear crystal and show that the scale of the process can be shrunk substantially. The approach should prove useful for developing miniaturized integrated quantum optical technologies. Science , this issue p. 1487

Metalens-array–based high-dimensional and multiphoton quantum source