Showing papers on "Equilibrium mode distribution published in 1971"

Multi-mode, monopulse feed system

Abstract: A wide band multi-mode feed device, capable of propagating a TE10 and a hybrid shaping mode is provided. A narrow ridge hybrid mode generator, disposed between a mode cavity and a mode phasor, controls a sum pattern E-plane shaping mode. The narrow ridge provides only a negligible coupling to the TE20 mode since the narrow ridges are placed only in the null regions of the TE20 mode. The mode cavity and an inverse mode launcher control unwanted cross polarization resulting from the TE11 and TM11 modes. This device is most useful for high efficiency monopulse antenna systems and especially for systems where the accurate gathering and analysis of tracking data is a prime requisite.

Stable resonators with increased fundamental mode volume for CO2 laser oscillators

Abstract: A method is described for designing a single mode CO2 laser cavity of high Fresnel number which oscillates in the fundamental transverse mode and a single longitudinal mode. A short, large bore cavity was constructed which oscillates in the TEM00 mode without the use of intracavity irises. The radii of curvature of the reflectors were designed using the Gaussian beam equations of Kogelnik and Li and an experimentally determined mode selection parameter.

A Laser Resonator with a Selector for a Higher Transverse Mode (Correspondence)

Abstract: A new laser resonator is proposed in which a specified higher order Hermite-Gaussian mode becomes the lowest loss mode. The two reflectors in the resonator are blocked in the vicinity of the characteristic zeros of the mode and the edge (i.e., |x|, |y| /spl rlarr2/ /spl infin/). In such a configuration the mode volume is enhanced, and mode selection is improved as compared with a conventional resonator in which a Gaussian mode is the dominant one. We have specialized to TEM/sub 22/ mode. The solutions to the integral equation for the eigenmodes and eigenvalues of the resonator are obtained on a digital computer. The computed eigenfunctions and mode selection show several interesting characteristics, and the loss mechanism for a few low-loss modes are elucidated. The computational results show that the location and the width of the blocking structure are closely related to the mode competition phenomenon and therefore mode selection.