A Stanford University team has created a tool that can automatically analyze the partial coherence of multimode spatial light fields, according to a study published in Light: Science & Applications.
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Anyone who has worked in an optics lab knows the extremes of light coherence: Laser beams are extremely coherent, creating distinct interference patterns employed in applications such as precise sensing or atomic manipulation.
However, light from sources like flashlights is incoherent and usually cannot create such patterns without a lot of work or at the expense of significant optical power losses.
Light exhibits partial coherence in most practical scenarios, with characteristics between these extremes. This partial coherence can manifest across multiple degrees of freedom of light, including spatial and temporal (frequency) components, making its study and manipulation complicated but necessary.
The device measures and controls the light’s coherency matrix using a network of cascaded interferometer layers, effectively separating the light into mutually incoherent components (such as two distant emitting points on the surface of a flashlight).
The technology is based on integrated photonics platforms and employs arrays of reconfigurable Mach-Zehnder interferometers. These arrays enable precise manipulation and real-time adjustment of the optical properties of the input light, which adapt dynamically to changes in coherence.
This innovative technique could greatly improve advanced imaging systems, environmental sensing, and the creation of more efficient optical communications systems. These developments could improve practical technology deployment and scientific research by offering a better understanding and control of light coherence.
Journal Reference:
Roques-Carmes, C. et. al. (2024) Measuring, processing, and generating partially coherent light with self-configuring optics. Light: Science & Applications. doi.org/10.1038/s41377-024-01622-y