Fabry-Pérot angle sensor using a mode-locked femtosecond laser source

Area of Science:

• Optical Engineering
• Metrology
• Laser Physics

Background:

• Accurate angle measurement is crucial in various scientific and industrial applications.
• Traditional angle sensors face limitations in precision and resolution.

Purpose of the Study:

• To propose and verify a new angle sensor design utilizing multiple beam interference.
• To enhance the accuracy of angle determination using a femtosecond laser and Fabry-Pérot etalon.

Main Methods:

• Employing a mode-locked femtosecond laser as the measurement beam.
• Utilizing a Fabry-Pérot etalon for multiple beam interference.
• Detecting fringe spectra from transmittance and reflectance sides and dividing their intensities to enhance visibility.
• Evaluating output angles using estimated local maxima of the processed fringe spectra.

Main Results:

• The proposed method significantly increases the visibility of fringe spectra by narrowing the spectrum width.
• Repeating measurements 100 times confirmed improved evaluation accuracies.
• The accuracy of angle determination was improved by one order of magnitude compared to conventional methods.

Conclusions:

• The developed angle sensor based on Fabry-Pérot etalon and femtosecond laser interference offers superior accuracy.
• The technique of dividing transmittance and reflectance spectra effectively enhances measurement precision.
• This method presents a feasible and highly accurate solution for angle metrology.