Disclosed is a medical laser system for treating a target tissue with a laser beam which comprises an optical fiber with a fiber tip for guiding the laser beam to the target tissue, the target tissue being immersed in a liquid medium formed primarily of water, the system configured to: fire, at a first time (T1) and along a light path, an initiation pulse (10); and fire, at a second time (T2) following the first time (T1) by a predetermined time delay (t) and along the same light path, a treatment pulse (20). The initiation pulse (10) is characterized by a first energy (E'), and the treatment pulse is characterized by a second energy (Et), wherein an absorbed energy in the liquid medium located between the fiber tip and the target tissue creates a bubble in a short delay after the first time (T1), and wherein the treatment pulse (20) is fired during a period the bubble is collapsing.