Angular spectrum method with compact space-bandwidth: generalization and full-field accuracy.

Area of Science:

• Optics and Photonics
• Computational Electromagnetics
• Wave Propagation Modeling

Background:

• The modified angular spectrum method (ASM) offers efficient wave propagation calculations.
• Existing ASM techniques are limited in handling propagation between two defocus planes.
• Accurate wave field calculations require careful consideration of space-bandwidth product (SBP).

Purpose of the Study:

• To generalize the modified ASM for propagation between two defocus planes.
• To reduce the numerical space-bandwidth product (NSBP) required for wave field calculations.
• To ensure high accuracy of the wave propagation simulations.

Main Methods:

• Employing paraxial spherical phase factors and modified propagation kernels.
• Utilizing Wigner distribution analysis to assess the evolution of the generalized SBP.
• Deriving sampling criteria based on space-frequency constraints and zero padding.

Main Results:

• The proposed method effectively handles propagation between defocus planes.
• Wigner distribution analysis confirms high accuracy across the computational domain.
• A small amount of zero padding significantly enhances the method's capability.
• Computational and memory gains exceed two orders of magnitude compared to conventional ASM.

Conclusions:

• The generalized modified ASM provides an accurate and computationally efficient solution for wave propagation between defocus planes.
• The method offers substantial improvements in computational speed and memory usage.
• This advancement is crucial for various optical system designs and simulations.