A. Fluctuation phenomena in quantum optics. B. The construction of a CO 2 TEA laser

Chi‐Wai Chow

Published Aug 1, 1975• 0 citations

Abstract

This dissertation may be divided into three parts. In the first part we propose and analyze the use of quantum beat phenomena to test neoclassical radiation theory (NCT) and quantum electrodynamics CQED). For a beam foil type of experiment with atoms having one upper level and two closely spaced lower levels, all coherently excited, NCT predicts the presence of quantum beats in the emitted radiation; beats are not expected in QED. QED predicts beats when many atoms are pres ent, in agreement with recent photon-echo experiments. An experiment to test NCT and QED is suggested. In the second part of this dissertation we calculate, via the quantum noise operator approach, the power spectral density of a laser subjected to a symmetry-breaking injected signal. The resulting spec trum is sharpened. It is further noted that these considerations are potentially of interest in producing high intensity fields in small focal volumes. The final portion of this dissertation contains a description of a high power CO2 TEA laser that was built for use in laser isotope separation experiments. This laser, whose output pulses are each of the order of a few joules, will be used in studies concerning the laser enrichment of SF^ and the temporal behavior of hot electrons in InSb.

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Joseph H. Eberly, L. Mandeļ, E. Wolf

W1 Resonant Pulse Propagation I.- W1-1 Some Nonlinear Properties of Pulse Propagation.- W1-2 Self-Induced Transparency in the Broadline and Narrowline Limits and Applications.- W1-3 Observation of Zero-Degree Pulse Propagation in a Resonant Medium.- W1-4 Higher Conservation Laws and Coherent Pulse Propagation.- W2 Quantum Electrodynamics and Alternative Theories I.- W2-1 Survey of the Present Status of Neoclassical Radiation Theory.- W2-2 A Test of Jaynes' Neoclassical Theory: Incoherent Resonance Fluorescence from a Coherently Excited State.- W2-3 Experimental Limitations to the Validity of Semiclassical Radiation Theories.- W2-4 Time Delay Statistics of Photoelectric Emissions: An Experimental Test of Classical Radiation Theory.- W3 Coherence Effects in Spontaneous Emission I.- W3-1 Non-Linear Radiation Reaction.- W3-2 Master Equations in the Theory of Incoherent and Coherent Spontaneous Emission.- W3-3 Influence of Resonant Frequency Shifts on Superradiant Damping.- W3-4 Spontaneous Emission Rate in the Presence of a Mirror.- W4 Coherence I.- W4-1 Atomic Coherent States in Quantum Optics.- W4-2 Coherent States in Modern Physics.- W4-3 Debye Representation and Multipole Expansion of the Quantized Free Electromagnetic Field.- W4-4 Volume of Coherence.- T1 Quantum Electrodynamics and Alternative Theories II.- T1-1 A Quantum Treatment of Spontaneous Emission without Photons.- T1-2 Finite Quantum and Classical Electrodynamics.- T1-3 The Use of Classical Solutions in Quantum Optics.- T1-4 Raman Effect in Semiclassical Theory.- T2 Light Scattering I.- T2-1 Theory of Resonant Light Scattering Processes in Solids.- T2-2 A Generalized Extinction Theorem and Its Role in Scattering Theory.- T2-3 Mode Analysis and Mode Coupling of Electromagnetic Fields in Spatially Dispersive Media.- T2-4 Amplitude Stabilization of Pulses from a Q-Switched Ruby Laser by Means of Interaction with a Non-Linear Medium.- T3 Correlation and Fluctuation Measurements.- T3-1 Two-Photon Time Distributions in Mixed Light Beams.- T3-2 Photocounting Inversion in Presence of Dead Time Effects.- T3-3 Image Reconstruction from the Modulus of the Correlation Function: A Practical Approach to the Phase Problem of Coherence Theory.- T3-4 Photon-Correlation Spectroscopy.- T3-5 Multi-Time Intervals Distributions of Photoelectrons from Stationary Pseudo-Thermal Light with Gaussian Spectrum.- T4 Light Scattering II.- T4-1 Adventures in Green's Land: Light Scattering in Anisotropic Media.- T4-2 Intensity Fluctuation Techniques in Light Scattering.- T4-3 Coherence Properties of Light through a Liquid Crystal.- T4-4 C. 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Lasing in strongly scattering dielectric microstructures

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In the first part of this thesis, a detailed analysis of lasing in random multiple-light-scattering media with gain is presented. Random laser emission is analyzed using a time-dependent diffusion model for light propagating in the medium containing active atoms. We demonstrate the effects of scatterers to narrow the emission spectral linewidth and to shorten the emitted pulse duration at a specific threshold pump intensity. This threshold pump intensity decreases with scatterer density and excitation spot diameter, in excellent agreement with experimental results. The coherence properties of the random laser are studied using a generalized master equation. The random laser medium is treated as a collection of low quality-factor cavities, coupled by random photon diffusion. Laser-like coherence, on average, is demonstrated above a specific pumping threshold. We demonstrate that with stronger scattering, the pumping threshold for the transition from chaotic to isotropic coherent light emission decreases and enhanced optical coherence for the emitted light is achieved above threshold. The second part of this thesis presents a study of lasing in photonic crystals (PCs). The emission from an incoherently pumped atomic system in interaction with the electro-magnetic reservoir of a PC is analyzed using a set of generalized semiclassical Maxwell-Bloch equations. We demonstrate that the photonic band edge facilitates the enhancement of stimulated emission and the reduction of internal losses, leading to an important lowering of the laser threshold. In addition, an increase of the laser output at a photonic band edge is demonstrated. We next develop a detailed quantum theory of a coherently pumped two-level atom in a photonic band gap material, coupled to both a multi-mode wave-guide channel and a high-quality micro-cavity embedded within the PC. The cavity field characteristics are highly distinct from that of a corresponding high-Q cavity in ordinary vacuum. We demonstrate enhanced, inversionless, and nearly coherent light generation when the photon density of states (DOS) jump between the Mollow spectral components of atomic resonance fluorescence is large. In the case of a vanishing photon DOS on the lower Mollow sideband and no dipolar dephasing, the emitted photon statistics is Poissonian and the cavity field exhibits quadrature coherence.

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Quantum-beat phenomena described by quantum electrodynamics and neoclassical theory

Weng W. Chow, Marlan O. Scully, John O. Stoner

We propose and analyze the use of quantum-beat phenomena to test neoclassical radiation theory (NCT) and quantum electrodynamics (QED). For a beam-foil type of experiment with atoms having one upper level and two closely spaced lower levels, all coherently excited, NCT predicts the presence of quantum beats in the emitted radiation; beats are not expected in QED. QED predicts beats when many atoms are present, in agreement with recent photon-echo experiments. An experiment to test NCT and QED is suggested.

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Colored noise in dye laser fluctuations

R. Roy, A. W. Yu, Shitong Zhu

Introduction The investigation of the coherence properties of light sources has traditionally involved the study of correlation functions of different orders of the electric field (Born and Wolf, 1975; Mandel and Wolf, 1965). Field and intensity correlation functions have been measured for laser light (for a review, see Lax and Zwanziger, 1973) and have been compared with predictions obtained from quantum laser theory (Haken, 1970, 1981; Lax, 1969; Louisell, 1973; Sargent, Scully and Lamb, 1974). This was, in fact, one of the major confirmations of the correctness of the basic formalism of quantum laser theory. Most of the experiments that probed the coherence properties of lasers were, however, carried out on a very limited variety of lasing media. Interest was also centered on the regime of operation near threshold, where the light from the laser is extremely weak; hence photoelectron counting and correlation techniques were developed for the measurement of coherence properties of the laser light. While these early experiments were performed with the main intent of testing the basic theory, the large variety of lasers now available, and their ever more demanding applications, make it necessary to develop new methods for the measurement and analysis of laser fluctuations. These techniques should be applicable to the measurement of noise in high power lasers; at the same time, in order to delineate the limits of usage, they must be sensitive enough to quantitatively determine the quantum mechanical sources of noise which may lie buried in external noise that is many orders of magnitude larger.

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High resolution spectroscopy using a CW stabilized dyelaser

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