Fiber optic sensor for nondestructive detection of microbial growth on a silk surface

To nondestructively detect the mold growth process on silk, a coaxial concave reflection conical fiber optic sensor was developed using conical quartz fibers, fiber connectors, fiber couplers, and a plastic fixator. We established a theoretical model of this sensor and studied the influence of its structural parameters on its sensitivity, characterized the morphology of Aspergillus niger, and detected its growth process on a silk surface. A linear relationship between the sensor's output signal and the mold height was found. The sensor sensitivity, maximum detection error, and low limit of detection were 2.4 E-5 AU/µm, 7.83%, and 10 µm, respectively.