A damage detection system includes one or more emitters, one or more receivers, and a controller. Emitters are arranged to transmit continuous beam or intermittent light pulses toward rotor blades during operation of a turbomachine. Light returns collected at the receivers define a light return amplitude profile. The controller analyzes the light return amplitude profile to identify light amplitude changes indicative of one or more damaged blades. When the light return profile satisfies one or more damage criteria, the controller outputs an indication of blade damage to another turbomachine controller, system, or display.