Overview
- The MIT group reported Monday in Nature Methods that a multimode fiber laser can self-organize into a narrow “pencil beam.”
- The effect appears only when the laser enters the fiber at a perfect zero-degree angle and the power is raised until the light interacts nonlinearly with the glass.
- Tests showed a more stable and tightly focused beam with fewer halo-like sidelobes and a longer in-focus range, which sharpens images across depth.
- Using the beam, the team captured 3D images of engineered human blood–brain barrier tissue about 25 times faster than a gold-standard method with comparable resolution, and they tracked cellular uptake of proteins without fluorescent tags.
- The approach needs strict alignment and operation near power levels that risk damaging the fiber, and the researchers plan deeper physics studies, broader biological uses such as neuronal imaging, and steps toward commercialization.