Answer:
A laser-Doppler vibrometer identifies the Doppler effect or shift of laser light reflected from the sample object
Step-by-step explanation:
A laser-Doppler vibrometer (e.g. Micro Motion Analyzer 400 from Polytec) identifies the Doppler effect or shift of laser light reflected from the sample object .At a beam splitter, a laser beam is partitioned into a measuring beam and a reference beam that deflects 90 ° upwards and transmit to the reference mirror "RM." Both beams come back to the beam splitter.