How could we noninvasively distinguish between healthy and cancerous tissue? And how could we increase the speed of wireless communications? These two seemingly unrelated questions may share the same answer: terahertz (THz) light. Spanning frequencies between 0.3 and 20 THz, THz light interacts with matter without causing damage and allows for faster data transfer than radio waves. It is thus ideal for advancing many applications in biomedicine and telecommunications, for which simple yet sensitive and fast detectors are needed.