Janssen Theory and Architecture Guides

This documentation provides comprehensive coverage of the physics and software architecture underlying janssen, a JAX-based framework for optical microscopy simulations and ptychographic reconstruction.

Target Audience

These guides are written for optics researchers who want to understand:

  • The mathematical foundations of coherent and partially coherent optics

  • How optical wavefronts propagate through the simulation pipeline

  • The physical meaning of simulation parameters and outputs

Guide Overview

Physics Foundations

Guide

Description

Partial Coherence

Spatial and temporal coherence, mode decomposition

Optical Propagation

Fresnel, Fraunhofer, and Angular Spectrum methods

Ptychography

Phase retrieval algorithms (ePIE, gradient-based)

Zernike Polynomials

Optical aberrations and wavefront decomposition

Vector Optics

High-NA focusing with Richards-Wolf integrals

Architecture

Guide

Description

PyTree Architecture

JAX data structures for GPU acceleration

JAX Sharp Edges

Common pitfalls and how to avoid them

Mathematical Notation

Throughout these guides, we use:

  • $\lambda$ for wavelength (in meters)

  • $k = 2\pi/\lambda$ for wavenumber

  • $\mathbf{E}$ for electric field

  • $I = |\mathbf{E}|^2$ for intensity

  • $\phi$ for phase