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Full-Text Articles in Engineering
Rotating-Wave Approximation In High-Gain Lasers, Lee W. Casperson
Rotating-Wave Approximation In High-Gain Lasers, Lee W. Casperson
Electrical and Computer Engineering Faculty Publications and Presentations
Semiclassical models for lasers typically incorporate a fundamental simplification called the rotating-wave approximation. In this study the rotating-wave approximation is reexamined, and its implications for the simplest problem of a steady-state laser oscillator are considered in detail. It is found that for practical laser operating conditions the errors resulting from this approximation may not always be negligible.
New Speckle Technique For Noncontact Measurement Of Small Creep Rates, Donald D. Duncan, F. Fausten Mark, Lawrence W. Hunter
New Speckle Technique For Noncontact Measurement Of Small Creep Rates, Donald D. Duncan, F. Fausten Mark, Lawrence W. Hunter
Electrical and Computer Engineering Faculty Publications and Presentations
A highly sensitive method for measuring thermal expansion, mechanical strain, and creep rates has been developed. This technique is based on Yamaguchi's speckle strain gauge concept, but uses a novel data-processing approach that provides estimates of the time rate of inplane strain. The approach is appropriate for assessing very small strain rates in hostile environments. It provides simultaneous global estimates of the strain at both small and large gauge sizes. This may be of importance in studying materials with different short- and long-range orders. General advantages of the technique are compact design, modest resolution requirements, insensitivity to surface microstructure changes …