Book contents
- Frontmatter
- Contents
- Dedication
- Preface
- 1 Quantum theory of radiation
- 2 Coherent and squeezed states of the radiation field
- 3 Quantum distribution theory and partially coherent radiation
- 4 Field–field and photon–photon interferometry
- 5 Atom–field interaction – semiclassical theory
- 6 Atom–field interaction – quantum theory
- 7 Lasing without inversion and other effects of atomic coherence and interference
- 8 Quantum theory of damping – density operator and wave function approach
- 9 Quantum theory of damping – Heisenberg–Langevin approach
- 10 Resonance fluorescence
- 11 Quantum theory of the laser – density operator approach
- 12 Quantum theory of the laser – Heisenberg–Langevin approach
- 13 Theory of the micromaser
- 14 Correlated emission laser: concept, theory, and analysis
- 15 Phase sensitivity in quantum optical systems: applications
- 16 Squeezing via nonlinear optical processes
- 17 Atom optics
- 18 The EPR paradox, hidden variables, and Bell's theorem
- 19 Quantum nondemolition measurements
- 20 Quantum optical tests of complementarity
- 21 Two-photon interferometry, the quantum measurement problem, and more
- Index
14 - Correlated emission laser: concept, theory, and analysis
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Dedication
- Preface
- 1 Quantum theory of radiation
- 2 Coherent and squeezed states of the radiation field
- 3 Quantum distribution theory and partially coherent radiation
- 4 Field–field and photon–photon interferometry
- 5 Atom–field interaction – semiclassical theory
- 6 Atom–field interaction – quantum theory
- 7 Lasing without inversion and other effects of atomic coherence and interference
- 8 Quantum theory of damping – density operator and wave function approach
- 9 Quantum theory of damping – Heisenberg–Langevin approach
- 10 Resonance fluorescence
- 11 Quantum theory of the laser – density operator approach
- 12 Quantum theory of the laser – Heisenberg–Langevin approach
- 13 Theory of the micromaser
- 14 Correlated emission laser: concept, theory, and analysis
- 15 Phase sensitivity in quantum optical systems: applications
- 16 Squeezing via nonlinear optical processes
- 17 Atom optics
- 18 The EPR paradox, hidden variables, and Bell's theorem
- 19 Quantum nondemolition measurements
- 20 Quantum optical tests of complementarity
- 21 Two-photon interferometry, the quantum measurement problem, and more
- Index
Summary
As discussed in the last three chapters, the fundamental source of noise in a laser is spontaneous emission. A simple pictorial model for the origin of the laser linewidth envisions it as being due to the random phase diffusion process arising from the addition of spontaneously emitted photons with random phases to the laser field. In this chapter we show that the quantum noise leading to the laser linewidth can be suppressed below the standard, i.e., Schawlow–Townes limit by preparing the atomic systems in a coherent superposition of states as in the Hanle effect and quantum beat experiments discussed in Chapter 7. In such coherently prepared atoms the spontaneous emission is said to be correlated. Lasers operating via such a phase coherent atomic ensemble are known as correlated spontaneous emission lasers (CEL). An interesting aspect of the CEL is that it is possible to eliminate the spontaneous emission quantum noise in the relative linewidths by correlating the two spontaneous emission noise events.
A number of schemes exist in which quantum noise quenching below the standard limit can be achieved. In two-mode schemes a correlation between the spontaneous emisson events in two different modes of the radiation field is established via atomic coherence so that the relative phase between them does not diffuse or fluctuate. In a Hanle laser and a quantum beat laser this is achieved by pumping the atoms coherently such that every spontaneously emitting atom contributes equally to the two modes of the radiation, leading to a reduction and even vanishing of the noise in the phase difference.
- Type
- Chapter
- Information
- Quantum Optics , pp. 402 - 441Publisher: Cambridge University PressPrint publication year: 1997