Image based aberration retrieval using helical point spread functions.

Area of Science:

• Optical Engineering
• Wavefront Sensing
• Image Processing

Background:

• Wavefront aberrations degrade optical system performance.
• Accurate aberration measurement is crucial for system calibration and correction.
• Existing methods often require specific targets or complex setups.

Purpose of the Study:

• To develop a practical method for determining wavefront aberrations.
• To enable aberration measurement using an extended, unknown object.
• To efficiently retrieve aberration coefficients for optical system characterization.

Main Methods:

• Utilizes a phase diversity approach combined with a pupil-engineered, helical point spread function (PSF).
• Employs power cepstrum analysis for efficient retrieval of aberration coefficients.
• Solves a simple linear system of equations to determine aberration values.

Main Results:

• Successfully demonstrates the measurement of low-order Zernike modes (defocus, astigmatism, coma, trefoil) via Monte Carlo simulations.
• Experimental validation retrieves the two-dimensional aberration distribution of a test setup.
• The method effectively discriminates aberrated PSF from object features.

Conclusions:

• The presented approach offers a practical and efficient solution for wavefront aberration determination.
• It allows for aberration measurement without requiring a known point source.
• This technique is valuable for calibrating and correcting optical systems with extended, unknown scenes.