Page 8 - Fundamentals of Light Microscopy and Electronic Imaging

CONTENTS vii

7. PHASE CONTRAST MICROSCOPY
AND DARK-FIELD MICROSCOPY 97
Overview 97
Phase Contrast Microscopy 97
The Behavior of Waves from Phase Objects in Bright-Field Microscopy 99
The Role of Differences in Optical Path Lengths 103
The Optical Design of the Phase Contrast Microscope 103
Alignment 106
Interpretating the Phase Contrast Image 106
Exercise: Determination of the Intracellular Concentration of Hemoglobin in
Erythrocytes by Phase Immersion Refractometry 110
Dark-Field Microscopy 112
Theory and Optics 112
Image Interpretation 115
Exercise: Dark-Field Microscopy 116
8. PROPERTIES OF POLARIZED LIGHT 117
Overview 117
The Generation of Polarized Light 117
Demonstration: Producing Polarized Light with a Polaroid Filter 119
Polarization by Reflection and Scattering 121
Vectorial Analysis of Polarized Light Using a Dichroic Filter 121
Double Refraction in Crystals 124
Demonstration: Double Refraction by a Calcite Crystal 126
Kinds of Birefringence 127
Propagation of O and E Wavefronts in a Birefringent Crystal 128
Birefringence in Biological Specimens 130
Generation of Elliptically Polarized Light by Birefringent Specimens 131

9. POLARIZATION MICROSCOPY 135
Overview 135
Optics of the Polarizing Microscope 136
Adjusting the Polarizing Microscope 138
Appearance of Birefingent Objects in Polarized Light 139
Principles of Action of Retardation Plates
and Three Popular Compensators 139
Demonstration: Making a Plate from a Piece of Cellophane 143
Exercise: Determination of Molecular Organization in Biological Structures
Using a Full Wave Plate Compensator 148

10. DIFFERENTIAL INTERFERENCE CONTRAST (DIC)
MICROSCOPY AND MODULATION CONTRAST
MICROSCOPY 153
Overview 153
The DIC Optical System 153
DIC Equipment and Optics 155
The DIC Prism 157
Demonstration: The Action of a Wollaston Prism in Polarized Light 158