文摘
The influence of transmission medium on the focusing performance of gradient-index (GRIN) fiber probe is analyzed for the development and performance evaluation of the ultra-small probe. ABCD matrix transformation is employed to derive the functional relationship between the focusing performance of GRIN fiber probe and the refractive index of transmission medium and present the curve graphs of working distance, spot size and depth of field on refractive index of transmission medium. Under the same parameters, the working distance and the depth of field of GRIN fiber probe increase with the increase of refractive index of transmission medium, but the spot size remains the same. The result shows that transmission medium has a certain influence on the working distance and the depth of field of GRIN fiber probe but has nothing to do with spot size.