A system and method for performing stress measurement on rotating parts is disclosed. The system may include a laser assembly configured to emit a plurality of laser beams having different wavelengths, and a probe assembly mounted proximal to a rotatable part in a device. The probe assembly may be configured to output a reflected laser beam onto a first target on the rotatable part. The probe assembly may be configured to output another reflected laser beam onto a second target on the rotatable part. The probe assembly may include a redirector, and a lens assembly mounted proximal to the redirector and configured to converge the laser beams. The redirector may be configured to change the direction of each emitted laser beam.