Book contents
- Frontmatter
- Contents
- Preface
- Symbols and abbreviations
- 1 Introduction
- 2 Two-level atoms
- 3 Three-level effects
- 4 Internal degrees of freedom
- 5 Optical pumping
- 6 Optically anisotropic vapours
- 7 Coherent Raman processes
- 8 Sublevel dynamics
- 9 Two-dimensional spectroscopy
- 10 Nonlinear dynamics
- 11 Mechanical effects of light
- References
- Index
7 - Coherent Raman processes
Published online by Cambridge University Press: 13 October 2009
- Frontmatter
- Contents
- Preface
- Symbols and abbreviations
- 1 Introduction
- 2 Two-level atoms
- 3 Three-level effects
- 4 Internal degrees of freedom
- 5 Optical pumping
- 6 Optically anisotropic vapours
- 7 Coherent Raman processes
- 8 Sublevel dynamics
- 9 Two-dimensional spectroscopy
- 10 Nonlinear dynamics
- 11 Mechanical effects of light
- References
- Index
Summary
After the sequence of introductory chapters that collected the necessary tools, we are now ready to discuss complete experiments. The first type of experiment we consider is the creation and detection of order in multilevel atoms through coherent Raman processes. The atoms that we use to study these processes are rare earth ions in a crystal matrix. Enclosing them in a crystal allows long interaction times, but also makes it necessary to consider their interaction with neighbouring atoms.
Overview
Raman processes
Introduction
In the preceding chapters, we mentioned several types of Raman processes. Their common feature is a resonant change of the energy of the photons that interact with the material system. The energy of the scattered photons may be lower (Stokes process) or higher (anti-Stokes) than that of the incident photons. The energy difference is transferred to the material system, where it must match an energy level separation. The photon energy itself, however, does not have to match exactly a transition frequency of the medium. This is commonly expressed by the statement that the Raman scattering proceeds through a virtual state, represented by the dashed line in Figure 7.1. The presence of a real state of the atom, indicated by the full line, nevertheless increases the coupling efficiency, as discussed in Chapter 3.
The earlier sections on three-level effects and optical anisotropy dealt with the mathematical formalism of Raman processes, using generic level systems to describe them.
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- The Physics of Laser-Atom Interactions , pp. 248 - 279Publisher: Cambridge University PressPrint publication year: 1997