High Precision Position Measurement Method for Laguerre-Gaussian Beams Using a Quadrant Detector

Area of Science:

• Optics and Photonics
• Metrology and Measurement Science

Background:

• Quadrant detectors (QD) are widely used for beam position measurements.
• Conventional methods for Laguerre-Gaussian beams exhibit position errors due to detector parameters.
• Improving the accuracy of these measurements is crucial for various optical engineering applications.

Purpose of the Study:

• To develop a new analytical method for improving the position measurement accuracy of Laguerre-Gaussian beams on a quadrant detector.
• To introduce a position error compensation factor and the concept of effective radius to simplify the measurement model.

Main Methods:

• Incorporating detector diameter and gap size effects into the conventional QD position measurement formula.
• Developing a position error compensation factor.
• Proposing an effective radius concept to reduce model parameters.
• Deriving a new analytical expression and fitting it using the least square method.

Main Results:

• The proposed method significantly reduces maximum position error by up to 97.4% for a beam radius of 0.95 mm.
• Root mean square errors remain below 0.004 mm across different beam radii.
• Simulations confirm effective accuracy improvement for various beam radii.

Conclusions:

• The new analytical method effectively enhances the accuracy of quadrant detector measurements for Laguerre-Gaussian beams.
• The proposed approach offers a promising solution for engineering practices in beam position measurements.
• This method provides a more robust and precise way to determine beam positions.