Contamination particles sensor based on microfiber

To obtain the number and sizes of aerosols generated in the enclosed room of high power laser system, a method of microparticle detection with microfiber was demonstrated in enclosed room. The additional loss of microfiber, caused by adhered microparticles with different refractive indices and diameters, were researched and simulated based on the evanescent field theory. Microfibers were fabricated using hydrogen-oxygen flame-heated scanning fiber drawing method and placed in the high power laser facility for demonstration. The experimental results show that, 1 μm- and 2 μm-diameter contamination particles were detected by 1.5 μm-diameter microfiber. The diameter and the number of microparticle can be estimated by measuring the additional loss of the sensing unit. The relation between the additional loss and space environment cleanliness can be obtained. The simulated results agree well with the experimental results. (authors)