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Full-Text Articles in Engineering
Effects Of Focusing-Beam Field Variations On The Stability Of Laser Oscillators, Pitak Chenkosol, Lee W. Casperson
Effects Of Focusing-Beam Field Variations On The Stability Of Laser Oscillators, Pitak Chenkosol, Lee W. Casperson
Electrical and Computer Engineering Faculty Publications and Presentations
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.
Generalized Beam Matrices. Ii. Mode Selection In Lasers And Periodic Misaligned Complex Optical Systems, Lee W. Casperson, Anthony A. Tovar
Generalized Beam Matrices. Ii. Mode Selection In Lasers And Periodic Misaligned Complex Optical Systems, Lee W. Casperson, Anthony A. Tovar
Electrical and Computer Engineering Faculty Publications and Presentations
A generalized beam matrix method is used to investigate the mode structure of astigmatic misaligned optical systems with loss or gain. In these optical systems the usual real-argument polynomial-Gaussian beams are not eigenfunctions, and off-axis complex-argument polynomial beams must be used. New beam transformations for these complex-argument modes are reported. Stability criteria are developed, and mode selection in laser resonators that contain tilted, displaced, or curved complex optical elements is discussed.
Propagation Of Airy-Hermite-Gaussian Waveguide Modes In Free Space, Lee W. Casperson, O. M. Stafsudd, Leroy V. Sutter, Jonathan Gary Grossman
Propagation Of Airy-Hermite-Gaussian Waveguide Modes In Free Space, Lee W. Casperson, O. M. Stafsudd, Leroy V. Sutter, Jonathan Gary Grossman
Electrical and Computer Engineering Faculty Publications and Presentations
The cavity modes of metal strip waveguide lasers are most simply expressed in terms of Airy-Hermite-Gaussian functions. The free space propagation of the resulting beam modes has been examined, and both near- and far-field patterns have been calculated and measured. Phase plates may be useful for enhancing the far-field intensity.
Modes Of A Laser Resonator With A Retroreflecting Roof Mirror, Guosheng Zhou, Lee W. Casperson
Modes Of A Laser Resonator With A Retroreflecting Roof Mirror, Guosheng Zhou, Lee W. Casperson
Electrical and Computer Engineering Faculty Publications and Presentations
The self-consistent integral equation for the field distribution of the resonant modes in a resonator with a tilted retroreflecting roof mirror is solved. The field distribution in the direction of the roof can be described in terms of Hermite-Gaussian functions. The beam matrix for a retroreflecting roof is found, and a new type of resonator which does not need precise alignment is proposed.
Mode Properties Of Annular Gain Lasers, Lee W. Casperson, Mohammad Shabbir Shekhani
Mode Properties Of Annular Gain Lasers, Lee W. Casperson, Mohammad Shabbir Shekhani
Electrical and Computer Engineering Faculty Publications and Presentations
The properties of a new class of laser resonators are investigated theoretically and experimentally. In these lasers the radiation propagates longitudinally in an annular amplifying medium, and useful low loss modes can be obtained even when the axial region is obscured. Alignment characteristics and far field patterns are discussed, and experiments have been conducted using coaxial double-discharge CO₂ devices.
Gain And Dispersion Focusing In A High Gain Laser, Lee W. Casperson, Amon Yariv
Gain And Dispersion Focusing In A High Gain Laser, Lee W. Casperson, Amon Yariv
Electrical and Computer Engineering Faculty Publications and Presentations
The transverse modes of a laser resonator containing a medium with a strong radial gain profile differ greatly from the modes of a similar resonator containing a low gain medium. Focusing and defocusing effects result from the gain profile and from the associated dispersion profile. The dispersion focusing causes an asymmetry in the power output as the laser is tuned across the gain line. The theory has been verified using a high gain 3.51-µ xenon laser.