Reconstruction of Misalignment Aberrations for Cylindrical Surfaces with Complex Parameters in Pseudo Lateral...

Area of Science:

• Optical metrology
• Aspheric optics measurement
• Interferometry

Background:

• High-precision measurement of cylindrical surfaces with complex parameters (CSCPs) is crucial in optical metrology.
• Traditional two-dimensional pseudo lateral shearing interferometry (2DPLSI) for CSCPs suffers from misalignment aberrations due to non-rotational symmetry, degrading reconstruction accuracy.

Purpose of the Study:

• To develop a novel non-null testing method for CSCPs that overcomes the limitations of existing 2DPLSI techniques.
• To accurately reconstruct CSCPs by eliminating misalignment aberrations and improving measurement precision.

Main Methods:

• A novel non-null testing method involving translation of the cylindrical surface in orthogonal directions for shearing.
• Elimination of wavefront errors through second-order differencing.
• A reconstruction algorithm utilizing the partial derivative in the x-direction to recover wavefront errors of misalignment aberrations.

Main Results:

• The proposed method effectively reconstructs misalignment aberrations in CSCPs.
• Achieved a reconstructed cylindrical surface with a peak-to-valley (PV) of 0.45λ and root-mean-square (RMS) of 0.12λ.
• Demonstrated superior repeatability (better than λ/1000 RMS) compared to existing methods.

Conclusions:

• The novel non-null testing method enables high-precision recovery of complex cylindrical surfaces.
• The technique effectively addresses and corrects misalignment aberrations, offering comparable accuracy to null testing.
• The method shows significant potential for advanced optical metrology applications.