Search

Search Results

• 31. [Article] Gaussian Light Beams in Inhomogeneous Media

  Vector wave solutions are obtained for the propagation of beams of light in media having slow spatial variations of the gain, loss, or index of refraction. The formalism developed here is applicable to ...

  Citation × Citation Citation Abstract Copy Title: Gaussian Light Beams in Inhomogeneous Media Author: Casperson, Lee W. Year: 1973 Vector wave solutions are obtained for the propagation of beams of light in media having slow spatial variations of the gain, loss, or index of refraction. The formalism developed here is applicable to a wide range of problems, and an exa mple considered in detail is the propagation of off-axis beams in lenslike laser materials and optical waveguides. A procedure is also described for the diagnosis of localized dielectric inhomogeneities such as plasmas by means of Gaussian laser beams. Title: Gaussian Light Beams in Inhomogeneous Media Author: Casperson, Lee W. Year: 1973 Vector wave solutions are obtained for the propagation of beams of light in media having slow spatial variations of the gain, loss, or index of refraction. The formalism developed here is applicable to a wide range of problems, and an exa mple considered in detail is the propagation of off-axis beams in lenslike laser materials and optical waveguides. A procedure is also described for the diagnosis of localized dielectric inhomogeneities such as plasmas by means of Gaussian laser beams. Close

• 32. [Article] Rayleigh-Debye scattering with focused laser beams

  A focused beam technique has been developed for diagnosing the characteristics of individual particles within a polydisperse ensemble. In the Rayleigh-Debye approximation the scattered fields are related ...

  Citation × Citation Citation Abstract Copy Title: Rayleigh-Debye scattering with focused laser beams Author: Casperson, Lee W., Yeh, Cavour W. Year: 1978 A focused beam technique has been developed for diagnosing the characteristics of individual particles within a polydisperse ensemble. In the Rayleigh-Debye approximation the scattered fields are related to the orientation and properties of a scatterer by means of explicit analytic formulas. The results simplify when the particle size is small compared to the minimum beam diameter. Title: Rayleigh-Debye scattering with focused laser beams Author: Casperson, Lee W., Yeh, Cavour W. Year: 1978 A focused beam technique has been developed for diagnosing the characteristics of individual particles within a polydisperse ensemble. In the Rayleigh-Debye approximation the scattered fields are related to the orientation and properties of a scatterer by means of explicit analytic formulas. The results simplify when the particle size is small compared to the minimum beam diameter. Close

• 33. [Article] Field-Equation Approximations and Amplification in High-Gain Lasers: Numerical Results

  It has recently been shown that a field-equation time-derivative approximation that is commonly used in studies of laser-oscillator dynamics is not necessary and can lead to significant errors for some ...

  Citation × Citation Citation Abstract Copy Title: Field-Equation Approximations and Amplification in High-Gain Lasers: Numerical Results Author: Casperson, Lee W. Year: 1991 It has recently been shown that a field-equation time-derivative approximation that is commonly used in studies of laser-oscillator dynamics is not necessary and can lead to significant errors for some lasers. A related space-derivative approximation is widely used in studies of steady-state laser amplifiers. A more rigorous amplifier formalism is developed here, and the results are exact solutions of Maxwell’s equations. The improved model predicts a spatial instability, single mirror oscillation, and other interesting field behavior. Title: Field-Equation Approximations and Amplification in High-Gain Lasers: Numerical Results Author: Casperson, Lee W. Year: 1991 It has recently been shown that a field-equation time-derivative approximation that is commonly used in studies of laser-oscillator dynamics is not necessary and can lead to significant errors for some lasers. A related space-derivative approximation is widely used in studies of steady-state laser amplifiers. A more rigorous amplifier formalism is developed here, and the results are exact solutions of Maxwell’s equations. The improved model predicts a spatial instability, single mirror oscillation, and other interesting field behavior. Close

• 34. [Article] Plasma Diagnosis by Laser Beam Scanning

  A procedure is developed for determining the radial electron density and temperature profiles of a rotationally symmetric plasma. This high‐resolution technique involves measuring the deflection of laser ...

  Citation × Citation Citation Abstract Copy Title: Plasma Diagnosis by Laser Beam Scanning Author: Casperson, Lee W., Cheng, T. K. Year: 1975 A procedure is developed for determining the radial electron density and temperature profiles of a rotationally symmetric plasma. This high‐resolution technique involves measuring the deflection of laser beams incident transverse to the plasma. Diagnosis of a stable atmospheric pressure argon arc with CO₂ and He‐Ne laser beams yields results in good agreement with spectroscopic methods. Title: Plasma Diagnosis by Laser Beam Scanning Author: Casperson, Lee W., Cheng, T. K. Year: 1975 A procedure is developed for determining the radial electron density and temperature profiles of a rotationally symmetric plasma. This high‐resolution technique involves measuring the deflection of laser beams incident transverse to the plasma. Diagnosis of a stable atmospheric pressure argon arc with CO₂ and He‐Ne laser beams yields results in good agreement with spectroscopic methods. Close

• 35. [Article] Grazing Reflection of Gaussian Beams

  The reflectivities of most surfaces are higher for grazing or near-90-deg angles of incidence than for more perpendicular or near-zero-deg angles. Grazing-incidence configurations are especially important ...

  Citation × Citation Citation Abstract Copy Title: Grazing Reflection of Gaussian Beams Author: Casperson, Lee W. Year: 1999 The reflectivities of most surfaces are higher for grazing or near-90-deg angles of incidence than for more perpendicular or near-zero-deg angles. Grazing-incidence configurations are especially important in the development of lasers and optical systems that operate in the far-ultraviolet and soft-x-ray regions of the spectrum, where transparent or highly reflecting media are almost unknown. Analytical solutions of the paraxial wave equation are obtained for the grazing reflection and complex interference effects that take place when a Gaussian beam interacts at shallow angles with a reflecting surface. Title: Grazing Reflection of Gaussian Beams Author: Casperson, Lee W. Year: 1999 The reflectivities of most surfaces are higher for grazing or near-90-deg angles of incidence than for more perpendicular or near-zero-deg angles. Grazing-incidence configurations are especially important in the development of lasers and optical systems that operate in the far-ultraviolet and soft-x-ray regions of the spectrum, where transparent or highly reflecting media are almost unknown. Analytical solutions of the paraxial wave equation are obtained for the grazing reflection and complex interference effects that take place when a Gaussian beam interacts at shallow angles with a reflecting surface. Close

• 36. [Article] Effects of Focusing-Beam Field Variations on the Stability of Laser Oscillators

  Semiclassical models for the dynamical behavior of single-longitudinal-mode, homogeneously broadened, unidirectional ring-laser oscillators have long been available. However, in most of these models the ...

  Citation × Citation Citation Abstract Copy Title: Effects of Focusing-Beam Field Variations on the Stability of Laser Oscillators Author: Chenkosol, Pitak, Casperson, Lee W. Year: 2005 Semiclassical models for the dynamical behavior of single-longitudinal-mode, homogeneously broadened, unidirectional ring-laser oscillators have long been available. However, in most of these models the beam's cross section is assumed to be independent of longitudinal position in the laser, while in practical laser systems it is common for the diameter to vary with position. A model for lasers with focusing-beam field variations is developed here. Linear stability analysis shows that higher values of excitation are required to reach the type 1 instability threshold for lasers with longitudinal variations of the beam diameter than for the uniform plane-wave laser model. Title: Effects of Focusing-Beam Field Variations on the Stability of Laser Oscillators Author: Chenkosol, Pitak, Casperson, Lee W. Year: 2005 Semiclassical models for the dynamical behavior of single-longitudinal-mode, homogeneously broadened, unidirectional ring-laser oscillators have long been available. However, in most of these models the beam's cross section is assumed to be independent of longitudinal position in the laser, while in practical laser systems it is common for the diameter to vary with position. A model for lasers with focusing-beam field variations is developed here. Linear stability analysis shows that higher values of excitation are required to reach the type 1 instability threshold for lasers with longitudinal variations of the beam diameter than for the uniform plane-wave laser model. Close

• 37. [Article] Waterfall Lasers

  Laser concepts can be applied to a broad range of physical phenomena. One of the closest parallels occurs with the fluttering oscillations that are sometimes observed in the falling sheets of water associated ...

  Citation × Citation Citation Abstract Copy Title: Waterfall Lasers Author: Casperson, Lee W. Year: 1997 Laser concepts can be applied to a broad range of physical phenomena. One of the closest parallels occurs with the fluttering oscillations that are sometimes observed in the falling sheets of water associated with fountains, dams, and natural waterfalls. In many respects these fluid feedback oscillations are similar to the electromagnetic modes of typical lasers, and recognition of this similarity led to the interpretation of the waterfall behavior. Gain profiles for the waterfall oscillations are developed, and the relationship of experimental waterfall data to the laser-like models is considered in detail. Title: Waterfall Lasers Author: Casperson, Lee W. Year: 1997 Laser concepts can be applied to a broad range of physical phenomena. One of the closest parallels occurs with the fluttering oscillations that are sometimes observed in the falling sheets of water associated with fountains, dams, and natural waterfalls. In many respects these fluid feedback oscillations are similar to the electromagnetic modes of typical lasers, and recognition of this similarity led to the interpretation of the waterfall behavior. Gain profiles for the waterfall oscillations are developed, and the relationship of experimental waterfall data to the laser-like models is considered in detail. Close

• 38. [Article] Threshold characteristics of mirrorless lasers

  Detailed analytical expressions are developed for the output power and spectral characteristics of high‐gain mirrorless laser amplifiers. With regard to intensity variations and spectral narrowing, such ...

  Citation × Citation Citation Abstract Copy Title: Threshold characteristics of mirrorless lasers Author: Casperson, Lee W. Year: 1977 Detailed analytical expressions are developed for the output power and spectral characteristics of high‐gain mirrorless laser amplifiers. With regard to intensity variations and spectral narrowing, such lasers are similar in behavior to conventional laser oscillators. A threshold transition region is apparent as saturation sets in, and spectral rebroadening occurs in inhomogeneously broadened laser systems. These solutions take full account of saturation by both the right and left propagating radiation, and the results agree with experiments that have been reported. Title: Threshold characteristics of mirrorless lasers Author: Casperson, Lee W. Year: 1977 Detailed analytical expressions are developed for the output power and spectral characteristics of high‐gain mirrorless laser amplifiers. With regard to intensity variations and spectral narrowing, such lasers are similar in behavior to conventional laser oscillators. A threshold transition region is apparent as saturation sets in, and spectral rebroadening occurs in inhomogeneously broadened laser systems. These solutions take full account of saturation by both the right and left propagating radiation, and the results agree with experiments that have been reported. Close

• 39. [Article] Properties of a coaxial cw CO₂ laser

  A cw CO₂ laser has been developed in which the active medium is formed by a discharge between coaxial electrodes. The laser gain and saturation properties have been studied as functions of the various ...

  Citation × Citation Citation Abstract Copy Title: Properties of a coaxial cw CO₂ laser Author: Ken, T.-K. Cheng, Casperson, Lee W. Year: 1979 A cw CO₂ laser has been developed in which the active medium is formed by a discharge between coaxial electrodes. The laser gain and saturation properties have been studied as functions of the various device parameters. Over-all efficiency is about the same as for a conventional longitudinal discharge laser, and advantages of the coaxial geometry include low voltage operation, rapid cooling, and rugged construction. Title: Properties of a coaxial cw CO₂ laser Author: Ken, T.-K. Cheng, Casperson, Lee W. Year: 1979 A cw CO₂ laser has been developed in which the active medium is formed by a discharge between coaxial electrodes. The laser gain and saturation properties have been studied as functions of the various device parameters. Over-all efficiency is about the same as for a conventional longitudinal discharge laser, and advantages of the coaxial geometry include low voltage operation, rapid cooling, and rugged construction. Close

• 40. [Article] Rate-Equation Approximations in High-Gain Lasers

  The rate-equation approximation is one of the most fundamental and universally employed simplifications in laser analyses. The accuracy and regions of applicability of this approximation are explored in ...

  Citation × Citation Citation Abstract Copy Title: Rate-Equation Approximations in High-Gain Lasers Author: Casperson, Lee W. Year: 1997 The rate-equation approximation is one of the most fundamental and universally employed simplifications in laser analyses. The accuracy and regions of applicability of this approximation are explored in comparisons with more rigorous semiclassical models. Higher-order rate-equation approximations are also developed, and these improved models can yield much better accuracy than conventional rate equations with little added complexity. The modified adiabatic elimination methods reported here would also be useful in reducing the mathematical models governing other physical systems. Title: Rate-Equation Approximations in High-Gain Lasers Author: Casperson, Lee W. Year: 1997 The rate-equation approximation is one of the most fundamental and universally employed simplifications in laser analyses. The accuracy and regions of applicability of this approximation are explored in comparisons with more rigorous semiclassical models. Higher-order rate-equation approximations are also developed, and these improved models can yield much better accuracy than conventional rate equations with little added complexity. The modified adiabatic elimination methods reported here would also be useful in reducing the mathematical models governing other physical systems. Close