Imagine having the ability to manipulate light waves in order to see through a skull right into the brain, or being able to use lasers to diagnose a bacterial infection in a matter of minutes. At the Center for Biophotonic Sensors and Systems (CBSS) at Boston University, technologies enabling these abilities and many others are coming to light. With support from the National Science Foundation (NSF), mechanical engineer Thomas Bifano and his colleagues are developing optical microscopes that can image deep into biological tissue, helping scientists observe molecular-scale activity. Their goal is to revolutionize the diagnosis and treatment of disease. Part of the National Science Foundation Series “Science Nation.”