Optical Setup (IMAGE) Optica Caption Researchers developed a new optical cavity that improves the sensitivity of terahertz spectroscopy. It allows molecules under analysis interact with the terahertz frequencies over an effective distance of approximately 1 kilometer inside a resonator only 50 centimeters long. As the waves bounce around, they can be absorbed by molecules many times, allowing a very sensitive measurement. Credit Francis Hindle, Université du Littoral-Côte d'Opale Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.