Topic
Optical pumping
About: Optical pumping is a research topic. Over the lifetime, 14289 publications have been published within this topic receiving 236373 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: Schawlow and Townes as discussed by the authors proposed a technique for the generation of very monochromatic radiation in the infra-red optical region of the spectrum using an alkali vapour as the active medium.
Abstract: Schawlow and Townes1 have proposed a technique for the generation of very monochromatic radiation in the infra-red optical region of the spectrum using an alkali vapour as the active medium. Javan2 and Sanders3 have discussed proposals involving electron-excited gaseous systems. In this laboratory an optical pumping technique has been successfully applied to a fluorescent solid resulting in the attainment of negative temperatures and stimulated optical emission at a wave-length of 6943 A. ; the active material used was ruby (chromium in corundum). After demonstration in 1954 of the 'maser' principle (microwave amplification by stimulated emission of radiation), systems were sought in which the effect occurred in the infrared and visible spectrum. This goal was reached in 1960 when Theodore Maiman achieved optical laser action in ruby.
3,893 citations
Journal Article•
TL;DR: Schawlow and Townes as discussed by the authors proposed a technique for the generation of very monochromatic radiation in the infra-red optical region of the spectrum using an alkali vapour as the active medium.
Abstract: Schawlow and Townes1 have proposed a technique for the generation of very monochromatic radiation in the infra-red optical region of the spectrum using an alkali vapour as the active medium. Javan2 and Sanders3 have discussed proposals involving electron-excited gaseous systems. In this laboratory an optical pumping technique has been successfully applied to a fluorescent solid resulting in the attainment of negative temperatures and stimulated optical emission at a wave-length of 6943 A. ; the active material used was ruby (chromium in corundum). After demonstration in 1954 of the 'maser' principle (microwave amplification by stimulated emission of radiation), systems were sought in which the effect occurred in the infrared and visible spectrum. This goal was reached in 1960 when Theodore Maiman achieved optical laser action in ruby.
3,646 citations
TL;DR: It is demonstrated that optical pumping with circularly polarized light can achieve a valley polarization of 30% in pristine monolayer MoS(2), demonstrating the viability of optical valley control and valley-based electronic and optoelectronic applications in MoS (2) monolayers.
Abstract: Most electronic devices exploit the electric charge of electrons, but it is also possible to build devices that rely on other properties of electrons. Spintronic devices, for example, make use of the spin of electrons. Valleytronics is a more recent development that relies on the fact that the conduction bands of some materials have two or more minima at equal energies but at different positions in momentum space. To make a valleytronic device it is necessary to control the number of electrons in these valleys, thereby producing a valley polarization. Single-layer MoS(2) is a promising material for valleytronics because both the conduction and valence band edges have two energy-degenerate valleys at the corners of the first Brillouin zone. Here, we demonstrate that optical pumping with circularly polarized light can achieve a valley polarization of 30% in pristine monolayer MoS(2). Our results, and similar results by Mak et al., demonstrate the viability of optical valley control and valley-based electronic and optoelectronic applications in MoS(2) monolayers.
3,158 citations
TL;DR: Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on either semiconductor devices or the optical nonlinear Kerr effect, have dramatically improved these lasers and opened up new frontiers for applications with extremely short temporal resolution, extremely high peak optical intensities and extremely fast pulse repetition rates.
Abstract: Ultrafast lasers, which generate optical pulses in the picosecond and femtosecond range, have progressed over the past decade from complicated and specialized laboratory systems to compact, reliable instruments. Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on either semiconductor devices or the optical nonlinear Kerr effect, have dramatically improved these lasers and opened up new frontiers for applications with extremely short temporal resolution (much smaller than 10 fs), extremely high peak optical intensities (greater than 10 TW/cm2) and extremely fast pulse repetition rates (greater than 100 GHz).
1,914 citations
Book•
[...]
27 Aug 2012
TL;DR: In this paper, the authors present a survey of the most commonly used line-broadening and line-switching techniques for laser beams, including the following: 1.1.1 Semiclassical approach, 2.2.2 Allowed and Forbidden Transitions, and 3.3.3 Pumping Schemes.
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.
1,483 citations