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Electrical and Computer Engineering

Portland State University

Wave guides

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Full-Text Articles in Engineering

Power Self-Regulation In Double-Pass High-Gain Laser Amplifiers, Lee W. Casperson, Janet M. Casperson Mar 2000

Power Self-Regulation In Double-Pass High-Gain Laser Amplifiers, Lee W. Casperson, Janet M. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Double-pass laser amplifiers can provide automatic passive regulation of the power in an optical signal. This regulation can significantly reduce the amplitude noise on a laser beam that is intended as a continuous wave light source. Analytic expressions are derived to describe the optical-noise-reduction region of double-pass amplifier operation and the dependence of the self-regulation properties on gain, saturation, and mirror reflectivity.


Double-Pass High-Gain Laser Amplifiers, Janet M. Casperson, Frederick G. Moore, Lee W. Casperson Sep 1999

Double-Pass High-Gain Laser Amplifiers, Janet M. Casperson, Frederick G. Moore, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Double-pass laser amplifiers have advantages of compactness and efficiency in the amplification of optical signals, and such amplifiers have been employed in a wide range of optical systems. Work in this area is reviewed briefly, and analytical solutions are obtained for the intensity of the electromagnetic waves in double-pass homogeneously-broadened high-gain laser amplifiers. Expressions are derived relating the output power to the input, including the effects of arbitrary mirror reflectivity and frequency detuning from line center. In the limits of weak saturation and of high reflectivity the results are consistent with earlier studies.


Sinusoidal-Gaussian Beams In Complex Optical Systems, Lee W. Casperson, Dennis G. Hall, Anthony A. Tovar Dec 1997

Sinusoidal-Gaussian Beams In Complex Optical Systems, Lee W. Casperson, Dennis G. Hall, Anthony A. Tovar

Electrical and Computer Engineering Faculty Publications and Presentations

Sinusoidal-Gaussian beam solutions are derived for the propagation of electromagnetic waves in free space and in media having at most quadratic transverse variations of the index of refraction and the gain or loss. The resulting expressions are also valid for propagation through other real and complex lens elements and systems that can be represented in terms of complex beam matrices. The solutions are in the form of sinusoidal functions of complex argument times a conventional Gaussian beam factor. In the limit of large Gaussian beam size, the sine and cosine factors of the beams are dominant and reduce to the …


Direct Current-Excited Cw Co² Metal Waveguide Laser, Fahad S. Al-Mashaabi, Lee W. Casperson May 1989

Direct Current-Excited Cw Co² Metal Waveguide Laser, Fahad S. Al-Mashaabi, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

A novel design for a dc-excited cw CO₂ metal waveguide laser has been developed in which a slotted hollow cathode also doubles as a metal waveguide for the cavity modes. This design has been implemented in a compact structure that produces over 1 W of cw 10.6-µm radiation. The discharge characteristics, laser gain, and laser output have been studied as functions of various discharge parameters. The advantages of the transverse discharge of the slotted hollow cathode geometry include low voltage, positive impedance, rugged structure, and high optical gain. Overall efficiency is comparable with that of conventional longitudinal CO² lasers. The …


Metal Waveguide Modeling Of Tapered Quadratic Index Media, Lee W. Casperson, Bahram Zandi Dec 1986

Metal Waveguide Modeling Of Tapered Quadratic Index Media, Lee W. Casperson, Bahram Zandi

Electrical and Computer Engineering Faculty Publications and Presentations

The basic electromagnetic properties of tapered graded index fibers are equivalent to the properties of a class of concave metallic waveguides. Although useful in their own right, such metal waveguides also provide a straightforward and inexpensive means for studying the characteristics of more complicated tapered media.