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Fourier Optics & Course Box

The Fourier Optics / Course Box teaches the fundamental principles of microscopy and optical alignment. Originally designed for the "Principles of Light Microscopy" course at the Light Microscopy Facility of MPI-CBG in Dresden, this toolbox provides hands-on experience with the core concepts that make all microscopy methods possible.

Educational Philosophy​

This box is designed for microscopy courses targeting users rather than optical designers. It provides insight into the "black box" that microscopes often seem to be, with comprehensive alignment tutorials using basic components. By reusing components and building from common ground, it demonstrates that all microscopy methods are based on just a few fundamental principles.

What You'll Learn​

  • Core principles of light microscopy
  • Köhler illumination setup and alignment
  • Conjugate planes in microscopy
  • Finite vs. infinity-corrected optics
  • Fourier transform in optics (Abbe diffraction)
  • Practical optical alignment techniques
  • Ray diagrams and optical path design

Experiments in this Section​

1. Compound Microscope (Finite Optics)​

Build a finite-corrected microscope with proper Köhler illumination where all conjugate planes are accessible for learning.

Learn: Basic microscope design, Köhler illumination, finite optics, conjugate planes

2. Abbe Diffraction Experiment (Finite Optics)​

Classical experiment demonstrating the Fourier transform performed by a lens. Simultaneously observe the primary image plane and back focal plane using a beam splitter and relay lens.

Learn: Fourier optics, diffraction, spatial frequency filtering, back focal plane imaging

3. Compound Microscope (Infinity Optics)​

Build an infinity-corrected microscope with proper Köhler illumination, showing how modern microscopes are designed.

Learn: Infinity-corrected optics, tube lens function, modern microscope design

4. Abbe Diffraction (Infinity Optics)​

Reuse the infinity microscope setup with a laser pointer to demonstrate Fourier transform and diffraction principles in infinity-corrected systems.

Learn: Laser illumination, diffraction patterns, infinity space manipulation

5. Microscopy Alignment Procedures​

Detailed step-by-step alignment tutorials for both finite and infinity-corrected microscopes.

Learn: Köhler illumination alignment, centering techniques, optical axis alignment

Tutorials in this Section​

  • Microscopy Core Concepts - Introduction to the CourseBox and fundamental principles
  • Finite Optics Alignment - Complete alignment procedure for finite-corrected microscopes
  • Infinity Optics Alignment - Complete alignment procedure for infinity-corrected microscopes

Key Concepts Covered​

  • Köhler Illumination: Even sample illumination independent of light source structure
  • Conjugate Planes: Understanding image planes and illumination planes
  • Fourier Transform: How lenses perform spatial frequency transforms
  • Resolution: Factors determining microscope resolution
  • Numerical Aperture: Understanding NA and its effects
  • Optical Path Design: Ray tracing and optical system layout

Required Components​

  • LED light source or lamp
  • Condenser lens system
  • Field diaphragm
  • Aperture diaphragm
  • Microscope objectives (finite and infinity-corrected)
  • Tube lens (for infinity optics)
  • Eyepiece or camera
  • Beam splitter (for Abbe experiments)
  • Relay lens
  • Laser pointer (for diffraction experiments)
  • UC2 cubes and baseplates
  • Sample slides

Applications​

  • University microscopy courses
  • Optics education and training
  • Teaching basic principles before expensive microscope use
  • Hands-on learning for biology and physics students
  • Understanding how commercial microscopes work

Development​

The alignment procedure was developed and optimized by Sebastian Bundschuh, following lectures by Peter Evennett. This toolbox continues to evolve as more universities and institutions adopt it in their courses.

Perfect for educators teaching microscopy principles, students learning optics, and anyone who wants to understand what's really happening inside a microscope!