Physics Spotlight  
Yichen Shen. Photo: Denis Paiste/Materials Processing CenterYichen Shen
Photo: Denis Paiste/Materials Processing Cente

A mirror with a peephole

MIT graduate student Yichen Shen designs a photonic crystal system that lets light pass through at a specific angle.


When light shines through air onto water, some of the light usually will be reflected back into the air. But at one specific angle, called the Brewster angle, all of the p-polarized light travels into the water with no reflection. MIT graduate student Yichen Shen found a way to manipulate that Brewster angle in a specially designed photonic crystal mirror, achieving control over the light by controlling its angle of travel into a material.