S-Tapered Fiber Probe (IMAGE) Optica Caption Researchers designed a new sensor (a), based on an S-tapered fiber probe (STFP), that can be used for high sensitivity refractive-index measurement. When light from a broadband source (BBS) enters the fiber's tapered area, a portion of the light interacts with the surrounding sample in a way that shifts the light's spectrum (b). This altered light is reflected back through the fiber to an optical spectrum analyzer (OSA) that monitors and records the change in spectrum, providing information about the chemistry of the sample. Credit Chao Chen, Chinese Academy of Sciences 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.