- 标题
- 摘要
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- 实验方案
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An optical angle sensor based on chromatic dispersion with a mode-locked laser source
摘要： This paper proposes a new optical angle sensor, in which a mode-locked laser is employed as the light source, and chromatic dispersion of a collimator objective is utilized to detect the angular displacement of a target of interest. In the proposed method, each of the optical modes in the femtosecond laser beam reflected from the reflector mounted on a target of interest is separated from the others by chromatic dispersion of a collimator objective to generate a group of focused laser beams that can be utilized as the scale for measurement of an angular displacement of the target. By detecting the change in peak frequency in optical spectra obtained by the photodetector, a small angular displacement can be measured. In this paper, as the first step of research, a prototype optical setup is developed, and some basic experiments are carried out to demonstrate the feasibility of the proposed method for measurement of angular displacement.
关键词： Chromatic dispersion,Angular displacement,Angle measurement,Optical frequency comb,Laser autocollimation
更新于2025-11-28 14:24:03
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A New Optical Angle Measurement Method Based on Second Harmonic Generation with a Mode-Locked Femtosecond Laser
摘要： This paper proposes a new optical angle measurement method based on second harmonic generation with a mode-locked femtosecond laser source by taking use of the unique characteristic of high peak power and high-intensity electric field of the femtosecond laser pulses. The angle is measured from the second harmonic wave intensity, which is a function of the angle between the laser beam axis and the optic axis of a nonlinear crystal attached to the target of interest. It is found that the beta barium borate (BBO) crystal is suitable as the nonlinear crystal for this purpose through theoretical simulation. As the first step of research, an experimental demonstration is also carried out in such a way that a change of the second harmonic wave intensity due to the angular displacement of BBO crystal is measured to verify the feasibility of the proposed principle of the angle measurement method.
关键词： Angle measurement,Second harmonic generation,Femtosecond laser
更新于2025-09-12 10:27:22
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Small-angle measurement in laser autocollimation based on a common-path compensation method
摘要： In this study, a common-path compensation method is proposed for the laser beam drift resulting from the air parameters to enhance the stability of small-angle measurement in laser autocollimation. The measuring and reference beams generated with this method can propagate along approximately the same route such that the drifts in the two beams are nearly equal. Therefore, the angular drift of the measuring beam can be adequately compensated by that of the reference beam. The compensation principle was analyzed, and the experimental results revealed that, with three types of air parameter disturbances, the static measurement stability was better than 0.193 arcsec in 100 min after compensation, and the compensation rate was higher than 86.6%. Additionally, the dynamic measurement stability was 0.227 arcsec in 50 s after compensation, and the compensation rate was 53.6%. It is confirmed that the proposed method is effective for laser autocollimation.
关键词： Laser autocollimation,angle measurement,stability,common-path compensation,drift,air parameter
更新于2025-09-11 14:15:04