Air coupled vibration detection of all-fiber laser Doppler vibrometer

Key words: laser techn Using optical heterodyne detection, an all-fiber laser Doppler vibrometer (LDV) was set up to investigate the air coupled vibration of scattering objects so as to recover the vibrating information of the source. Influence of the scattering object properties, such as materials, holdings, relative positions to the source, etc. , on the response to the source vibration through air coupling was investigated by the LDV and the vibration frequency response curves ranging from 200 Hz to 2700 Hz for six scattering materials were obtained. Results show that in the case of air coupled vibration of scattering objects, the response vibration amplitude is generally bigger at higher frequency; and the vibration response curve is more affected by the material of the scattering object than by the holdings or relative positions of the scattering object. ique; laser Doppler vibrometer; vibration response; optical heterodyne detection