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J. Eur. Opt. Society-Rapid Publ. 21, 32( 2025)
Figure 10. Air flow turbulence of 1 m / s,( a) 2-D in-plane result,( b) at( 60, 60) pixel.
measured. Noise reduction using pre-filter was also described and the sub-nanometer resolution was suggested. Since this interferometer was specifically designed for highspeed cameras, relatively huge optical components such as EOM, BE, and DM were introduced, resulting in a much longer optical path length than previously reported [ 13 ]. This may cause air fluctuations and noise due to the low stiffness of the mechanical components in the frequency range below 100 Hz. Shortening the optical path length of the interferometer and increasing the rigidity of the mechanical components may reduce these noise levels.
As future work, one improvement and one development may be attempted. The improvement is to modify the current interferometer configuration( optics and its arrangements) to improve mechanical stiffness, air fluctuation robustness, and interferometric resolution. The development is to increase the modulation frequency to 2 MHz using a high modulation frequency EOM and a high frame rate HSC.
Funding
We express our gratitude to the Research Fund of Japan Society for the Promotion of Science( Grant Number: 20H02042) for supporting this research. We would also like to thank Chuo Precision Industrial Co. Ltd., for valuable discussions.
Conflicts of interest The authors declare that they have no conflict of interests.
Data availability statement
The research data associated with this article are included within the article.
Author contribution statement
Higuchi proposed the idea and the calculation, carried out the experiments, and wrote the manuscript. All co-authors participated in the discussion of the theory and experimental results. All authors read and approved of the final.
Glossary
2D Two dimensional, BE Beam expander, BS Beam splitter, DM Deformable mirror, EOM Electro-optic modulator, EUV Extreme ultraviolet, FPGA field programmable gate array, HSC Highspeed camera, HWP Half wave plate, P Polarizer, PBS Polarization beam splitter, PLL Phase-locked loop, PM Plane mirror, PZT Piezoelectric transducer, QWP Quarter wave plate, SPM Sinusoidal phase modulation.
References
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