Development and application of VISAR probe with higher signal-collecting efficiency and adjusted depth of field

The new design of optical fiber VISAR probes has been described. It consists of optical fibers and two lenses, and has simpler structure and lower cost than others. If the size of the image near the end face of collecting fiber is larger than the diameter of the core fiber, the distance between the probe and the target can be decreased. Requirement for the precision in the design is lower in this way, and is easier to build up. At the same time, the signal-collecting efficiency is improved in some degree. During the process of designing the probe, the technique for manufacturing the lens of plexiglass is developed. The lens of plexiglass is used to replace the lens of glass, which can reduce the cost of the probe. The factors affecting the collecting efficiency are analyzed