Book contents
- Frontmatter
- Contents
- Preface to the second English edition
- Preface to the first edition
- Introduction
- 1 Abbe's sine condition
- 2 Fourier optics
- 3 Effect of polarization on diffraction in systems of high numerical aperture
- 4 Gaussian beam optics
- 5 Coherent and incoherent imaging
- 6 First-order temporal coherence in classical optics
- 7 The van Cittert–Zernike theorem
- 8 Partial polarization, Stokes parameters, and the Poincaré sphere
- 9 Second-order coherence and the Hanbury Brown–Twiss experiment
- 10 What in the world are surface plasmons?
- 11 Surface plasmon polaritons on metallic surfaces
- 12 The Faraday effect
- 13 The magneto-optical Kerr effect
- 14 The Sagnac interferometer
- 15 Fabry–Pérot etalons in polarized light
- 16 The Ewald–Oseen extinction theorem
- 17 Reciprocity in classical linear optics
- 18 Optical pulse compression
- 19 The uncertainty principle in classical optics
- 20 Omni-directional dielectric mirrors
- 21 Linear optical vortices
- 22 Geometric-optical rays, Poynting's vector, and the field momenta
- 23 Doppler shift, stellar aberration, and convection of light by moving media
- 24 Diffraction gratings
- 25 Diffractive optical elements
- 26 The Talbot effect
- 27 Some quirks of total internal reflection
- 28 Evanescent coupling
- 29 Internal and external conical refraction
- 30 Transmission of light through small elliptical apertures
- 31 The method of Fox and Li
- 32 The beam propagation method
- 33 Launching light into a fiber
- 34 The optics of semiconductor diode lasers
- 35 Michelson's stellar interferometer
- 36 Bracewell's interferometric telescope
- 37 Scanning optical microscopy
- 38 Zernike's method of phase contrast
- 39 Polarization microscopy
- 40 Nomarski's differential interference contrast microscope
- 41 The van Leeuwenhoek microscope
- 42 Projection photolithography
- 43 Interaction of light with subwavelength structures
- 44 The Ronchi test
- 45 The Shack–Hartmann wavefront sensor
- 46 Ellipsometry
- 47 Holography and holographic interferometry
- 48 Self-focusing in nonlinear optical media
- 49 Spatial optical solitons
- 50 Laser heating of multilayer stacks
- Index
- References
6 - First-order temporal coherence in classical optics
Published online by Cambridge University Press: 31 January 2011
- Frontmatter
- Contents
- Preface to the second English edition
- Preface to the first edition
- Introduction
- 1 Abbe's sine condition
- 2 Fourier optics
- 3 Effect of polarization on diffraction in systems of high numerical aperture
- 4 Gaussian beam optics
- 5 Coherent and incoherent imaging
- 6 First-order temporal coherence in classical optics
- 7 The van Cittert–Zernike theorem
- 8 Partial polarization, Stokes parameters, and the Poincaré sphere
- 9 Second-order coherence and the Hanbury Brown–Twiss experiment
- 10 What in the world are surface plasmons?
- 11 Surface plasmon polaritons on metallic surfaces
- 12 The Faraday effect
- 13 The magneto-optical Kerr effect
- 14 The Sagnac interferometer
- 15 Fabry–Pérot etalons in polarized light
- 16 The Ewald–Oseen extinction theorem
- 17 Reciprocity in classical linear optics
- 18 Optical pulse compression
- 19 The uncertainty principle in classical optics
- 20 Omni-directional dielectric mirrors
- 21 Linear optical vortices
- 22 Geometric-optical rays, Poynting's vector, and the field momenta
- 23 Doppler shift, stellar aberration, and convection of light by moving media
- 24 Diffraction gratings
- 25 Diffractive optical elements
- 26 The Talbot effect
- 27 Some quirks of total internal reflection
- 28 Evanescent coupling
- 29 Internal and external conical refraction
- 30 Transmission of light through small elliptical apertures
- 31 The method of Fox and Li
- 32 The beam propagation method
- 33 Launching light into a fiber
- 34 The optics of semiconductor diode lasers
- 35 Michelson's stellar interferometer
- 36 Bracewell's interferometric telescope
- 37 Scanning optical microscopy
- 38 Zernike's method of phase contrast
- 39 Polarization microscopy
- 40 Nomarski's differential interference contrast microscope
- 41 The van Leeuwenhoek microscope
- 42 Projection photolithography
- 43 Interaction of light with subwavelength structures
- 44 The Ronchi test
- 45 The Shack–Hartmann wavefront sensor
- 46 Ellipsometry
- 47 Holography and holographic interferometry
- 48 Self-focusing in nonlinear optical media
- 49 Spatial optical solitons
- 50 Laser heating of multilayer stacks
- Index
- References
Summary
A truly monochromatic beam of light, if it ever existed, would be perfectly coherent. Suppose that such a beam is split into two parts and each part propagated over an arbitrary distance. When the parts are finally brought together and mixed, no matter how different the two path lengths may have been, the resulting waveform will exhibit constructive and destructive interference in the form of bright and dark fringes. The coherence length of a monochromatic beam is therefore infinite, in the sense that the path-length difference can be as large as desired without hampering one's ability to create interference patterns.
Real sources of light, of course, are never monochromatic. white light restricted to the visible range of wavelengths from 400 nm to 700 nm, for example, has a coherence length of only a couple of micrometers. A green filter passing sunlight at λ0 = 550 nm with a 10 nm bandwidth produces a beam with a coherence length of about 50 μm. The red line of cadmium (λ0 = 643.8 nm) has a nearly Gaussian spectrum with a 0.0013 nm width at half peak intensity, leading to a coherence length of nearly 30 cm. This is similar to the coherence length of a short, inexpensive HeNe laser (λ0 = 632.8 nm) with a few longitudinal modes and a typical bandwidth of Δf ≈ 1 GHz. A stabilized HeNe laser operating in a single longitudinal mode (Δf ≈ 100 kHz) has a coherence length of several kilometers.
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- Chapter
- Information
- Classical Optics and its Applications , pp. 74 - 87Publisher: Cambridge University PressPrint publication year: 2009