Fiber laser carving under ice layer without laser energy attenuation

•A novel method of laser carving under ice layer without laser energy attenuation is proposed.•The accuracy of machined channel width would not be affected at the condition of laser carving under ice.•A thermal effect model of laser beam on ice layer and workpiece is developed.•The recast layer and dross is well removed.•High temperature influence area, heat effect zone and surface oxidation are decreased.