Lateral shearing interferometer with variable shearing for measurement of a small beam

Area of Science:

• Optics and Photonics
• Optical Metrology

Background:

• Accurate measurement of small beams is critical in various scientific and industrial applications.
• Existing interferometers may lack the flexibility for precise control over shearing amount.

Purpose of the Study:

• To propose and validate a new lateral shearing interferometer with variable shearing for small beam measurement.
• To demonstrate continuous adjustment of shearing amount and acquisition of 2D interferograms.

Main Methods:

• Utilizing a polarization beam splitter, thick birefringent plate, quarter-wave plate, and mirror.
• Employing a thick birefringent plate as a shear generator for tiny shearing amounts.
• Achieving variable shearing by rotating the birefringent plate and obtaining 2D interferograms via perpendicular rotations.

Main Results:

• Demonstrated that the shearing amount can be made tiny using the thick birefringent plate.
• Showcased continuous adjustment of shearing amount by rotating the birefringent plate.
• Verified the interferometer's performance through simulation and experimental results, showing good agreement.

Conclusions:

• The proposed lateral shearing interferometer enables precise measurement of small beams with adjustable shearing.
• The system's ability to generate 2D interferograms and its verified accuracy confirm its usefulness in optical metrology.