XII CONTENTS
8.5.2 Circular Aperture 249
8.5.3 Gaussian Beam 251
8.5.4 Gaussian Beam in an Aperture 252
8.5.5 Depth of Field: Almost-Fraunhofer Diffraction 253
8.5.6 Summary of Special Cases 254
8.6 Resolution of an Imaging System 254
8.6.1 Definitions 255
8.6.2 Rayleigh Criterion 256
8.6.3 Alternative Definitions 257
8.6.4 Examples 258
8.6.5 Summary of Resolution 260
8.7 Diffraction Grating 260
8.7.1 Grating Equation 260
8.7.2 Aliasing 262
8.7.3 Fourier Analysis 262
8.7.4 Example: Laser Beam and Grating Spectrometer 265
8.7.5 Blaze Angle 266
8.7.6 Littrow Grating 266
8.7.7 Monochromators Again 266
8.7.8 Summary of Diffraction Gratings 267
8.8 Fresnel Diffraction 268
8.8.1 Fresnel Cosine and Sine Integrals 268
8.8.2 Cornu Spiral and Diffraction at Edges 270
8.8.3