Light guide probe for the generation of laser beam intersection images

The development and production of a universally usable probe for the generation of laser beam intersection images for flow visualization investigations are described. The application of light guides between laser and probe makes the system highly flexible in use and handling. The in and outcoupling of the laser radiation as well as the transmission characteristics of the gradient index fiber are discussed. The light power transmission is optimized by paying attention to laser beam coupling laws. The use of aspheric imaging lenses (cylindrical lenses) makes it possible to obtain light disks with defined dimensions. The optical calculation fundamentals required to that end, and an example of the design of a light guide probe with variable application possibilities are explained. The example of the visualization of a wind tunnel flow is given.