Multi-beam full-field laser Doppler vibrometer based on a high-speed area scan CMOS camera

Area of Science:

• Optical Metrology
• Mechanical Engineering
• Materials Science

Background:

• Multi-beam laser Doppler vibrometers (MB-LDVs) enable simultaneous multi-point vibration analysis.
• Current MB-LDV systems face limitations in measurement channels due to hardware complexity.
• Increasing measurement points in traditional MB-LDVs leads to significant hardware scaling challenges.

Purpose of the Study:

• To develop a full-field MB-LDV system with an expanded measurement capability.
• To overcome the hardware complexity limitations of conventional MB-LDVs.
• To enable simultaneous, high-density vibration measurements over an area.

Main Methods:

• Development of a full-field MB-LDV utilizing an array scan high-speed digital CMOS camera.
• Simultaneous vibration measurement across a 17x17 matrix array of points.
• Analysis of vibration in the frequency range of 0 to 25 kHz with low velocity noise (2-8 nm/s).

Main Results:

• The developed MB-LDV achieves simultaneous vibration measurements at 289 points (17x17).
• The system demonstrates velocity noise levels between 2 and 8 nm/s.
• Instantaneous velocity imaging is possible due to preserved phase information.

Conclusions:

• The array scan camera approach significantly simplifies MB-LDV hardware design.
• This compact MB-LDV enables shorter measurement times compared to scanning systems.
• The full-field MB-LDV provides enhanced capabilities for analyzing dynamic surface deformation and transient events.