CONTENTS 



I. INTRODUCTION TO PHASE MICROSCOPY 1 



1. Seeing Microscopic Particles 1 



2. Historical Background 3 



3. Optical Fundamentals 5 



II. AN ELEMENTARY THEORY OF PHASE MICROSCOPY . . 13 



1. Introductory Remarks 13 



2. Light Waves and Their Interference 14 



3. A Qualitative Explanation of Phase Microscopy 16 



3.1. Phenomena of All Microscopes 17 



3.2. Phenomena of Phase Microscopes 23 



3.3. Extension of the Elementary Theory to Object Fields Containing 



More Than One Particle 32 



3.4. Extension of the Elementary Theory to Object Specimens Having 



Periodic Structure 33 



3.5. Passage of the Undeviated and Deviated Waves from a Simply 



Periodic Object Grating through a Phase Microscope . . 34 



4. Representation of the Amplitude and Phase by Complex Numbers . 37 



5. Visual Effect Produced by a Complex Wave 40 



6. Representation of the Undeviated and Deviated Waves ... 42 



7. Representation of the Modified Undeviated and Deviated Waves . 45 



8. Distribution of Energy Density over the Image Plane .... 47 



9. Condition for Darkest Contrast of the Particle 49 



10. Darkest Contrast with Particles Whose Amplitude Transmission is 



Equal to That of the Surround 50 



11. Darkest Contrast with Particles Differing from Their Surround Only 



in Absorption 53 



12. Equality of the Amplitudes of the Undeviated and Deviated Waves at 



the Conditions for Darkest Contrast 54 



13. Conditions for Optimum Bright Contrast 55 



14. Choice of Diffraction Plate with Particles Having Small Optical Path 



Differences and the Amplitude Ratio g = I 57 



15. Choice of Diffraction Plate with Stained Particles Whose Refractive 



Index Efjuals That of the Surround 61 



16. Choice of Diffraction Plate with Stained Particles Whose Optical Path 



Difference is +X /4 63 



17. Generalization of the Theory to More Than One Object Particle . 65 



18. Effect of the Diffraction Plate on Resolving Power .... 67 



III. INSTRUMENTATION 75 



1. General Considerations of Design 75 



2. The Diffraction Plate 87 



XI 



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