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Displacement Sensing for Laser Self-Mixing Interferometry by Amplitude Modulation and Integral Reconstruction
Yidan Huang1, Wenzong Lai1, Enguo Chen1,2
1National & Local United Engineering Laboratory of Flat Panel Display Technology, College of Physics and Information Engineering, Fuzhou University, Fuzhou 350108, China.
Sensors (Basel, Switzerland)
|June 27, 2024
Summary
We developed a new method for displacement sensing using self-mixing interferometry (SMI). This amplitude modulation integral reconstruction method (AM-IRM) accurately reconstructs displacement, even with noisy signals.
Area of Science:
- Optics and Photonics
- Signal Processing
- Metrology
Background:
- Self-mixing interferometry (SMI) is a technique for displacement sensing.
- Traditional methods face challenges with low-frequency signals and frequency blurring.
- Accurate displacement reconstruction is crucial for various applications.
Purpose of the Study:
- To propose a robust and adaptive method for displacement reconstruction in SMI systems.
- To overcome limitations of existing signal processing techniques like Continuous Wavelet Transform (CWT).
- To enhance the precision and applicability of SMI for real-world scenarios.
Main Methods:
- Amplitude Modulation Integral Reconstruction Method (AM-IRM) is introduced.
- SMI signal is multiplied with a high-frequency sinusoidal carrier to shift its spectrum.
- Synchrosqueezing Wavelet Transform (SSWT) is used for enhanced Doppler frequency resolution.
Main Results:
- Experimental displacement reconstruction accuracy achieved was 21.1 nm (0.89%).
- Simulations showed accurate reconstruction with time-varying optical feedback and SNR of 0 dB (max RMS error 22.2 nm).
- The method demonstrates robustness in challenging, real-world conditions.
Conclusions:
- AM-IRM offers a precise and robust solution for displacement sensing in SMI.
- The method simplifies implementation by avoiding manual parameter tuning and additional optical components.
- This technique shows significant potential for practical applications requiring accurate displacement measurements.
