Researchers at MIT have discovered that chaotic laser light can self-organize into a highly focused pencil beam, enabling 3D imaging of the blood-brain barrier 25 times faster than current methods. The technique allows real-time observation of drugs entering brain cells without fluorescent tags. This breakthrough could speed up development of treatments for neurological diseases like Alzheimer's and ALS.
A team led by Sixian You, an assistant professor in MIT's Department of Electrical Engineering and Computer Science, observed the unexpected behavior while testing a multimode optical fiber. As graduate student Honghao Cao increased laser power near the fiber's damage threshold, the light concentrated into a stable, sharp beam instead of scattering due to imperfections. You noted, 'The common belief in the field is that if you crank up the power in this type of laser, the light will inevitably become chaotic. But we proved that this is not the case.'