Dissecting the Dynamic Response of an ultra-fast Actuated Mirror

This application note illustrates how SmarAct’s PICOSCALE Vibrometer enables detailed analysis of the dynamic response of piezo-actuated mirrors. By measuring individual components—the bare piezo ring, mirror surface, and titanium mount—the system reveals how each part contributes to the overall mechanical resonance behavior. This method supports optimization of actuator design for high-speed optical systems by identifying hidden vibrational modes across a broad frequency range.

Problem

The dynamic behavior of piezo-actuated systems depends not only on the piezo element itself, but also on mechanical components such as the mount and the actuated object. Simulations alone often fail to capture the true system response due to production tolerances and assembly effects.

Solution

The PICOSCALE Vibrometer provides a contactless, high-resolution analysis of mechanical vibrations across individual components. Using laser scanning and lock-in detection, it enables modal imaging and amplitude spectrum acquisition from 10 kHz to 800 kHz

Implementation

• A frequency sweep was applied to a ring-shaped piezo resting on a damping pad.

• The same excitation was repeated for the assembled mirror surface and the titanium mount, with the laser focused on each respective surface.

• At each resonance, vibrational modes were visualized using 2D raster scans.

Results

• The bare piezo exhibited multiple low-frequency bending modes (e.g. 108, 182, 250 kHz).

• Once assembled, the mirror introduced new, dominant resonances (e.g. 175, 280, 375 kHz) not seen in the piezo alone.

• The mount displayed distinct lower-amplitude resonances (e.g. 215, 275, 634 kHz), shaped by its geometry and mass.

Conclusion

SmarAct’s PICOSCALE Vibrometer enables comprehensive characterization of system dynamics, revealing how individual parts shape the overall mechanical response. This capability is essential for refining designs of fast, piezo-driven actuators in precision optical systems.