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Full-Text Articles in Engineering
Beam Modes In Complex Lenslike Media And Resonators, Lee W. Casperson
Beam Modes In Complex Lenslike Media And Resonators, Lee W. Casperson
Electrical and Computer Engineering Faculty Publications and Presentations
General sets of higher-order beam modes are derived for light propagation in media having spatial variations of the gain or loss. The resulting expressions are also valid for propagation through conventional optical elements and graded transmission filters. The four basic mode sets obtained include off-axis Hermite-Gaussian and Laguerre-Gaussian modes of both real and complex argument. A procedure is developed for finding the resonant modes of laser oscillators containing arbitrary complex lens elements, and the mode stability properties of lasers can be interpreted physically by means of these formulas.
Pulse Evolution In Co₂ Lasers, Lee W. Casperson, M. J. Herbst, John J. Turechek
Pulse Evolution In Co₂ Lasers, Lee W. Casperson, M. J. Herbst, John J. Turechek
Electrical and Computer Engineering Faculty Publications and Presentations
Explicit formulas are examined for the development of optical pulses in gain‐switched or Q‐switched laser oscillators and for the distortion of such pulses in succeeding stages of laser amplification. The results are compared to data obtained with a TEA CO₂ oscillator‐amplifier system.
Analytic Modeling Of Gain‐Switched Lasers. Ii. Laser Amplifiers, Lee W. Casperson
Analytic Modeling Of Gain‐Switched Lasers. Ii. Laser Amplifiers, Lee W. Casperson
Electrical and Computer Engineering Faculty Publications and Presentations
The pulse transfer characteristics of gain‐switched laser amplifiers are investigated analytically. New closed‐form solutions have been obtained including arbitrary space‐ and time‐dependent pump distributions. The general results are specialzied to the important cases of uniform and traveling‐wave excitation. Input‐pulse shapes considered include step functions, practial oscillator output pulses, and also the inherent spontaneous‐emission noise. The results lead to improved models for pulse amplifiers and mirrorless traveling‐wave lasers. By proper choice of pump characteristics arbitrary output‐pulse waveforms can be synthesized.
Analytic Modeling Of Gain‐Switched Lasers. I. Laser Oscillators, Lee W. Casperson
Analytic Modeling Of Gain‐Switched Lasers. I. Laser Oscillators, Lee W. Casperson
Electrical and Computer Engineering Faculty Publications and Presentations
Detailed mathematical models are derived for the evolution of light pulses in gain‐switched laser oscillators. Unlike previous instantaneous‐switching models, arbitrary pump and spontaneous relaxation rates are considered. Explicit expressions are obtained for the gain and pulse characteristics in several practical situations, and both homogeneous and inhomogeneous limits are considered. By proper adjustment of the laser pump any output‐pulse shape can be obtained. The results are especially relevant for recent short‐pulse ultraviolet lasers and also for more conventional devices such as TEA CO₂ lasers.