I= QUANTUM STUDIES OF THE FILED IN A MICROMASER
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Title of Thesis
QUANTUM STUDIES OF THE FILED IN A MICROMASER

Author(s)
Mudassar Aqueel Ahmad
Institute/University/Department Details
Department of Physics & Applied Mathematics/ Institute of Engineering & Applied Sciences Islamabad
Session
2007
Subject
Physics
Number of Pages
119
Keywords (Extracted from title, table of contents and abstract of thesis)
quantum studies, micromaser, quantum phase fluctuations, two-photon micromaser, one-photon micromaser, quantum phase properties, cavity eigenmodes, inject atomic coherence

Abstract
The one-atom maser or micromaser has been a system of fundamental interest in quantum optics. It provides an experimental realization of the Jaynes-Cummings model. As compared to the ordinary laser, field inside a micromaser exhibits a number of interesting features. In this thesis, we consider the problem of quantum phase fluctuations of the field generated in one and two-photon micromaser. In a one-photon micromaser, we discuss the effect of cooperative atomic interactions, cavity losses, and pump fluctuations on quantum phase properties of the field. We consider, initial coherent state of the radiation field and atoms initially in the excited and coherent superposition of their atomic states, respectively. We find that quantum phase properties of the field in a micromaser are highly sensitive to two-atom events and cavity losses. Both contribute to the randomization of the well defined phase structure associated with the initial coherent state. However, the approach towards the randomization is quite different in the two cases. We also find that the fluctuations, associated with the random injection of the atoms, affect the phase structure of the coherent state.

Next, we study the quantum phase properties of the field in a two-photon micromaser, including the effects of the finite detuning of the intermediate level. For initial coherent state of the cavity field and atoms initially in their excited state multipeak phase structure appears which eventually leads to the randomization of the cavity field phase. However, the approach towards the randomization depends upon the detuning. If the atoms are injected in a coherent superposition of their upper and lower atomic states then the phase distribution evolves into two-peak structure. For initial thermal state and atoms in polarized state, cavity field acquires some phase. We also consider the effect of the finite Q of the cavity and random injection of the atoms in our system.

Finally, we discuss the effects of spatial mode function in a one-photon micromaser in the presence of two-atom events. It is shown that two-atom events allow us a possibility to study the effects of different cavity eigenmodes in a micromaser. We find that squeezing properties of the radiation field depend upon the parity (odd or even) and order (lower or higher) of cavity eigenmodes. For example, squeezing can be obtained for odd-order cavity eigenmodes which completely vanishes for even-order modes. Our results also show that effects similar to self-induced transparency which are studied in Jaynes-Cummings model with atomic motion are never obtained in a micromaser in the presence of two-atom events.

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4351.55 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
521.44 KB
2 1 Introduction 9
788.07 KB
  1.1 One-Photon Micromaser 11
  1.2 Two-Photon Micromaser 12
  1.3 Cooperative Atomic Interactions 14
  1.4 Quantum Phase 15
  1.5 Spatial Variation Of The Cavity Filed 21
3 2 Quantum Phase Properties Of The Field In A One-Photon Micromaser 23
1228.79 KB
  2.1 Model 23
  2.2 Review Of The Pegg -Barnett Hermitian Phase Formalism 29
  2.3 Phase Properties Of The Field In The Presence Of Cooperative Atomic Interaction 30
  2.4 Effect Of Cavity Losses And Pump Fluctuations One Quantum Phase Properties Of The Filed In A Micromaser 43
4 3 Quantum Phase Properties Of The Field In A Two-Photon Micromaser 55
866.5 KB
  3.1 Model 55
  3.2 Phase Properties Of The Micromaser Field: The Case Of No Inject Atomic Coherence 58
  3.3 Phase Properties Of The Micromaser Field: The Case Of Inject Atomic Coherence 70
5 4 Role Of Spatial Mode Function In The Presence Of Two-Atom Events In A Micromaser 78
826.05 KB
  4.1 Model 79
  4.2 Squeezing And Average Photo Numbers In The Presence Of Spatical Mode Function 86
  4.3 Numerical Results 87
6 5 Conclusions 100
681.35 KB
  5.1 Atom-Filed Density Matrix Elements For Two-Atom Events 104
  5.2 Bibliography 111