Laser Doppler Vibrometer
The World's Smallest Compact Laser Doppler Vibrometer
What Is a Compact Laser Doppler Vibrometer?
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It’s a miniaturized, chip-based laser vibrometer built using integrated photonics, allowing a full optical interferometer—including beamsplitters, delay lines, and demodulation networks—to be fabricated on a single chip
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Device dimensions can be as small as 58 × 34 × 22 mm, weighing under 100 g (e.g., the “MotionGo” model).
How the Compact Laser Doppler Vibrometer Works?
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Uses a homodyne interferometer configuration paired with multiple integrated quadrature demodulation (I/Q) networks for accurate measurement and error compensation.
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A primary I/Q demodulator reads vibration signals, while secondary and tertiary I/Q demodulators track and compensate for laser drift, temperature effects, or ghost reflections, ensuring signal stability and high accuracy despite environmental variations.
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Advantages Over Conventional LDVs
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Direct displacement measurement via phase demodulation—unlike traditional LDVs, which measure velocity and then integrate to displacement.
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Despite its compact form, it delivers wide frequency coverage (0.1 Hz to 1 MHz), high repeatability (≤0.5% variation), high accuracy (≤1% deviation vs. Polytec LDV), and robustness to surface conditions, maintaining SNR even on rough, unprepared surfaces.
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An actual version (MotionGo) supports sampling at 5 Msps, measures over distances up to 100 m, vibration velocities up to 20 m/s, with a noise floor under 0.1 nm, and low power consumption (≤1.5 W), enabling battery-powered mobile deployment (e.g. on drones or robotic arms).
