Researchers have developed a microscopic 3D-printed optical device that can efficiently combine light from dozens of small semiconductor lasers into a single multimode optical fiber with very low loss. The team demonstrated photonic lanterns that multiplex 7, 19, and 37 multimode VCSEL lasers directly into a fiber while preserving brightness and easing alignment constraints. By enabling scalable incoherent beam combining of many multimode lasers, the technology could simplify and improve high-power laser systems, optical communications, and other photonic applications where efficiently delivering large optical power through fibers is critical.

In Physics of Fluids, researchers model the way snow gathers on a roof based on snowflake size and distribution. The model considers how turbulence can affect recently landed snow and how wind can affect its gathering. Higher wind speeds will interrupt accumulation, reducing depth, but the effects of particle size on accumulation are all heightened under higher wind conditions — larger particles will be more resistant to the wind, and smaller ones will accumulate less.

In Physics of Fluids, researchers develop a computational model of outdoor airflow through trees to study how a tree’s geometry affects the dispersion of its airborne pollen grains. They modeled the porosity of a tree and incorporated an algorithm sensitive to small wind forces, taking into account the force required to detach a pollen grain. They applied their techniques to various known structures, compared the outcomes to real data, and found that the type and topology of a tree can lead to distinct pollen dispersion dynamics.

A Harvard study shows that snakes “stand” by focusing bending and muscle activity in a small region near their base.