Structured light

• Published in: Nature photonics Vol. 15; no. 4; pp. 253 - 262
• Main Authors: Forbes, Andrew, de Oliveira, Michael, Dennis, Mark R.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.04.2021; Nature Publishing Group
• Subjects: 639/624/400; 639/766/400/482; Angular momentum; Applied and Technical Physics; Degrees of freedom; Light; Physics; Physics and Astronomy; Quantum Physics; Qubits (quantum computing); Review Article
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/s41566-021-00780-4

All light has structure, but only recently has it been possible to control it in all its degrees of freedom and dimensions, fuelling fundamental advances and applications alike. Here we review the recent advances in ‘pushing the limits’ with structured light, from traditional two-dimensional transverse fields towards four-dimensional spatiotemporal structured light and multidimensional quantum states, beyond orbital angular momentum towards control of all degrees of freedom, and beyond a linear toolkit to include nonlinear interactions, particularly for high-harmonic structured light. Using a simple interference argument, centuries old, we weave a story that highlights the common nature of seemingly diverse structures, presenting a modern viewpoint on the classes of structured light, and outline the possible future trends and open challenges. Recent effort in controlling the structure of light in all its degrees of freedom and dimensions has pushed the limits of structured light and broadened its potential beyond orbital angular momentum, two-dimensional fields, qubits and biphotons, and linear optical manipulation.