Coated tilted fiber Bragg gratings are used for controlled heating of a limited area and for reading the local increase in temperature. Optical pumping at 1.8W produced a 7×15mm lesion in ex vivo porcine liver.
Optical Sensors, Sensors 2018
Department of Electronics

Alqarni, S.A. (Sondos A.), Albert, J, & Smelser, C. (2018). Fiber-grating-based hyperthermal therapeutic device for mm-sized ex vivo lethal volume. In Optics InfoBase Conference Papers. doi:10.1364/SENSORS.2018.SeM2E.4