By combining micro- and nanotechnology with ultrasonic actuation, engineers need new methods and instruments for characterizing mechanical responses at these frequencies and displacements. Laser-based, non-contact optical testing is the best choice since it avoids mass loading from direct contact.
Polytec’s new UHF-120 Vibrometer can characterize the out-of-plane vibrations at ultra-high frequencies, extending the vibration frequency bandwidth up to 1.2 GHz. Complete with a new optical design, the instrument retains the advantages and features familiar to laser vibrometer users. The system consists of a heterodyne interferometer with a controller box. The optical head provides a heterodyne detector signal that is acquired with a fast digital oscilloscope. The digitized detector signal is transferred to a PC where the heterodyne carrier is demodulated by a new software module in Polytec’s Vibsoft package.
The system has a gate function for reducing the output light power to minimize the energy transfer from the measurement beam to the structure and for easy alignment of the beam on the specimen. In addition, an integrated camera controls the measurement spot positioning using bright-field microscope illumination.