In this work, a low-cost multipoint fiber optic sensor system for real-time monitoring of the temperature distribution on transformer cores was demonstrated. The temperature sensors are based on multi-mode random air hole fibers infiltrated with CdSe/ZnS quantum dots. Quantum dots resided in multi-mode random-hole core regions can be optically excited by guided UV light with extremely high quantum efficiency. The photoluminescence intensity dependence on the ambient temperatures were used to gauge the local operational temperature of transformer under strong magnetic fields. Multiplepoint temperature sensing systems were developed by bundling quantum dots infiltrated random air hole fibers together. Using a low-cost UV diode laser as a light source and a CCD camera as detector, hundreds of fiber sensors can be interrogated at low cost. This multi-point fiber sensor system, which is free from electromagnetic interference, was used to monitor temperature fluctuation of transformer from the room temperature up to 96°C with better than 1°C accuracy. The proposed fiber optic sensing scheme could overcome the shortcomings of traditional electric sensors and provide a versatile and low-cost approach to map the temperature distribution of electric power systems such as transformers operated in strong electromagnetic fields.
Laser shock micro-forming is a non-thermal laser forming method that use laser-induced shockwave to modify surface
properties and to adjust shapes and geometry of work pieces. In this paper, we present an adaptive optical technique to
engineer spatial profiles of the laser beam to exert precision control on the laser shock forming process for free-standing
MEMS structures. Using a spatial light modulator, on-target laser energy profiles are engineered to control shape, size,
and deformation magnitude, which has led to significant improvement of the laser shock processing outcome at micrometer
scales. The results presented in this paper show that the adaptive-optics laser beam forming is an effective method
to improve both quality and throughput of the laser forming process at micrometer scales.
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