Fabry-Perot interferometers are optical devices that consist of two parallel, highly reflective mirrors that create multiple reflections to amplify the interference of light waves. In the context of cement and concrete, Fabry-Perot interferometers are utilized primarily for precision measurement of strain or deformation in structures. This technology is especially beneficial under severe environmental conditions, where monitoring the structural health of concrete can prevent catastrophic failures by detecting early signs of stress, deformation, or degradation.