A system for treating surface material overlying a substrate, and more particularly, to a system for ablating contaminates and other unwanted material from a worksite using a pulsed laser beam. The system includes three main sub-systems: a back end (30), a work head (100), and an umbilical tube (88) to protect conduits communicating between the back end (30) and the work head (100). The back end (30) includes heavy and bulky equipment such as a laser (32), chiller, pressurized air source (70), suction system, waste containment system, and electric power source (78). A conveyance such as a trailer may enclose the back end (30) to make it transportable. The work head (100) includes lightweight equipment such as scanning mirrors, optics, and camera (130). During operation, the work head (100) is pressed against the surface material and the laser (32) activated. Then scanning mirrors within the work head (100) arrange pulses from the laser beam according to a selected raster and dither pattern and direct them to the surface material. Ablated detritus may be suctioned through a conduit through the work head (100) and thence to the waste containment system in the back end (30). Electric power, laser energy, control and monitor signals, air, and suction are transported between the back end (30) and the work head (100) through the conduits encased within the umbilical tube (88).