Behavior of Bubble Induced by Fiber-Type Laser for TUL near Soft Wall with Deformability

A fiber-type laser induced bubble makes an important role on laser lithotripsy. This treatment can be affected by the circumference condition such as ureter tissue and a stone. In this study, we observed behavior of the bubble in a narrow space between two walls with different deformability. According to the present experimental results, a bubble symmetrically divides into two parts and collapses in the case of two walls with same hardness. The soft wall is deformed with bubble growth and collapse. In the case of walls with different hardness materials, the bubble which shows characteristic behavior asymmetrically divides, moves and collapses even if the bubble is formed at the center of two walls. The bubble moves toward wall direction during multiple collapses. The larger bubble collapse on the hard wall, that is, the impact is predicted to be larger on the rigid wall. It is found that bubble collapse pattern is greatly affected even by slight wall deformation.