Up-converted radio
Ever worry about losing your mobile-phone reception? The problem is a weak microwave signal. The same problem hampers cosmologists looking at the early universe, a glimpse embodied in the cosmic microwave background. Or take a pressing earthly example: oncologists often locate and identify tumors using MRI scans. All three of these efforts---communications, cosmology, medicine---depend on discriminating weak microwave or radio signals from a noisy environment. A new approach to this important problem provides a clean, all-optical detection of microwaves and radiowaves ...









