Dye laser

Abstract: 1 Introductory Concepts.- 1.1 Spontaneous and Stimulated Emission, Absorption.- 1.1.1 Spontaneous Emission.- 1.1.2 Stimulated Emission.- 1.1.3 Absorption.- 1.2 The Laser Idea.- 1.3 Pumping Schemes.- 1.4 Properties of Laser Beams.- 1.4.1 Monochromaticity.- 1.4.2 Coherence.- 1.4.3 Directionality.- 1.4.4 Brightness.- Problems.- 2 Interaction of Radiation with Matter.- 2.1 Summary of Blackbody Radiation Theory.- 2.2 Absorption and Stimulated Emission.- 2.2.1 Rates of Absorption and Stimulated Emission.- 2.2.2 Allowed and Forbidden Transitions.- 2.2.3 Transition Cross Section, Absorption and Gain Coefficient.- 2.3 Spontaneous Emission.- 2.3.1 Semiclassical Approach.- 2.3.2 Quantum Electrodynamic Approach.- 2.3.3 Einstein Thermodynamic Treatment.- 2.3.4 Radiation Trapping, Superradiance, Superfluorescence, and Amplified Spontaneous Emission.- 2.4 Nonradiative Decay.- 2.5 Line Broadening Mechanisms.- 2.5.1 Homogeneous Broadening.- 2.5.2 Inhomogeneous Broadening.- 2.5.3 Combined Effect of Line Broadening Mechanisms.- 2.6 Saturation.- 2.6.1 Saturation of Absorption: Homogeneous Line.- 2.6.2 Gain Saturation: Homogeneous Line.- 2.6.3 Inhomogeneously Broadened Line.- 2.7 Degenerate Levels.- 2.8 Relation between Cross Section and Spontaneous Radiative Lifetime.- 2.9 Molecular Systems.- 2.9.1 Energy Levels of a Molecule.- 2.9.2 Level Occupation at Thermal Equilibrium.- 2.9.3 Radiative and Nonradiative Transitions.- Problems.- References.- 3 Pumping Processes.- 3.1 Introduction.- 3.2 Optical Pumping.- 3.2.1 Pumping Efficiency.- 3.2.2 Pump Light Distribution.- 3.2.3 Pumping Rate.- 3.3 Electrical Pumping.- 3.3.1 Electron Impact Excitation.- 3.3.2 Spatial Distribution of the Pump Rate.- 3.3.3 Pumping Efficiency.- 3.3.4 Excitation by (Near) Resonant Energy Transfer.- Problems.- References.- 4 Passive Optical Resonators.- 4.1 Introduction.- 4.2 Plane-Parallel Resonator.- 4.2.1 Approximate Treatment of Schawlow and Townes.- 4.2.2 Fox and Li Treatment.- 4.3 Confocal Resonator.- 4.4 Generalized Spherical Resonator.- 4.4.1 Mode Amplitudes, Diffraction Losses, and Resonance Frequencies.- 4.4.2 Stability Condition.- 4.5 Unstable Resonators.- Problems.- References.- 5 Continuous Wave and Transient Laser Behavior.- 5.1 Introduction.- 5.2 Rate Equations.- 5.2.1 Four-Level Laser.- 5.2.2 Three-Level Laser.- 5.3 CW Laser Behavior.- 5.3.1 Four-Level Laser.- 5.3.2 Three-Level Laser.- 5.3.3 Optimum Output Coupling.- 5.3.4 Reasons for Multimode Oscillation.- 5.3.5 Single-Line and Single-Mode Oscillation.- 5.3.6 Two Numerical Examples.- 5.3.7 Frequency Pulling and Limit to Monochromaticity.- 5.3.8 Lamb Dip and Active Stabilization of Laser Frequency.- 5.4 Transient Laser Behavior.- 5.4.1 Spiking Behavior of Single-Mode and Multimode Lasers.- 5.4.2 Q-Switching.- 5.4.2.1 Methods of Q-Switching.- 5.4.2.2 Operating Regimes.- 5.4.2.3 Theory of Q-Switching.- 5.4.2.4 A Numerical Example.- 5.4.3 Mode Locking.- 5.4.3.1 Methods of Mode Locking.- 5.4.3.2 Operating Regimes.- 5 5 Limits to the Rate Equations.- Problems.- References.- 6 Types of Lasers.- 6.1 Introduction.- 6.2 Solid-State Lasers.- 6.2.1 The Ruby Laser.- 6.2.2 Neodymium Lasers.- 6.3 Gas Lasers.- 6.3.1 Neutral Atom Lasers.- 6.3.2 Ion Lasers.- 6.3.2.1 Ion Gas Lasers.- 6.3.2.2 Metal Vapor Lasers.- 6.3.3 Molecular Gas Lasers.- 6.3.3.1 Vibrational-Rotational Lasers.- 6.3.3.2 Vibronic Lasers.- 6.3.3.3 Excimer Lasers.- 6.4 Liquid Lasers (Dye Lasers).- 6.4.1 Photophysical Properties of Organic Dyes.- 6.4.2 Characteristics of Dye Lasers.- 6.5 Chemical Lasers.- 6.6 Semiconductor Lasers.- 6.6.1 Photophysical Properties of Semiconductor Lasers.- 6.6.2 Characteristics of Semiconductor Lasers.- 6.7 Color-Center Lasers.- 6.8 The Free-Electron Laser.- 6.9 Summary of Performance Data.- Problems.- References.- 7 Properties of Laser Beams.- 7.1 Introduction.- 7.2 Monochromaticity.- 7.3 First-Order Coherence.- 7.3.1 Complex Representation of Polychromatic Fields.- 7.3.2 Degree of Spatial and Temporal Coherence.- 7.3.3 Measurement of Spatial and Temporal Coherence.- 7.3.4 Relation between Temporal Coherence and Monochromaticity.- 7.3.5 Some Numerical Examples.- 7.4 Directionality.- 7.5 Laser Speckle.- 7.6 Brightness.- 7.7 Higher-Order Coherence.- Problems.- References.- 8 Laser Beam Transformation.- 8.1 Introduction.- 8.2 Transformation in Space. Gaussian Beam Propagation.- 8.3 Transformation in Amplitude: Laser Amplification.- 8.4 Transformation in Frequency: Second-Harmonic Generation and Parametric Oscillation.- 8.4.1 Physical Picture.- 8.4.1.1 Second-Harmonic Generation.- 8.4.1.2 Parametric Oscillation.- 8.4.2 Analytical Treatment.- 8.4.2.1 Parametric Oscillation.- 8.4.2.2 Second-Harmonic Generation.- Problems.- References.- 9 Applications of Lasers.- 9.1 Introduction.- 9.2 Applications in Physics and Chemistry.- 9.3 Applications in Biology and Medicine.- 9.4 Material Working.- 9.5 Optical Communications.- 9.6 Measurement and Inspection.- 9.7 Thermonuclear Fusion.- 9.8 Information Processing and Recording.- 9.9 Military Applications.- 9.10 Holography.- 9.11 Concluding Remarks.- References.- Appendixes.- A Space-Dependent Rate Equations.- B Physical Constants.- Answers to Selected Problems.

Abstract: Spectroscopic measurements and laser performance of Ti:Al2O3 are discussed in detail. Data on absorption and fluorescence spectra and fluorescence lifetime as a function of temperature are presented. Laser characteristics observed with pulsed-dye-laser, frequency-doubled Nd:YAG-laser, and argon-ion-laser pumping are covered and show that nearly quantum-limited conversion of pump radiation can be achieved, along with tuning over the wavelength range 660–986 nm.

Abstract: THE radiative properties of an atomic or molecular system may be altered significantly in the presence of coherent optical scattering1,2. In the course of investigating the radiative properties of a laser dye dispersed in a strongly scattering medium (a colloidal suspension of titanium dioxide particles), we have found that the emissions from such systems can exhibit spectral and temporal properties characteristic of a multimode laser oscillator, even though the systems contain no external cavity. The threshold excitation energy for laser action is surprisingly low. We suggest that these composite systems might find applications in laser instrumentation and photonics.

Abstract: An experimental and theoretical investigation of the fluctuations of the pulses from continuous-wave mode-locked lasers is presented. It is shown that these fluctuations can be detected and quantitatively characterized from measurements of the power spectrum of the light intensity. Such power spectra can be measured with great accuracy by shining the laser output on a suitable photodetector and by processing the detector signal with the use of an electronic spectrum analyzer. Different types of noise such as fluctuations of the pulse energy, pulse repetition time, and pulse duration, can be readily recognized from their characteristic spectral signature. Experimental results of noise measurements are presented for a synchronously mode-locked dye laser pumped by an acousto-optically mode-locked argon ion laser, and also for a colliding pulse passively mode-locked dye laser.