Cathodes for HeNe Lasers

Abstract

Vapor deposited aluminum cathodes for parallel plate HeNe lasers have been used with considerable success. It is shown that the aluminum cold cathode is improved by the addition of copper and that other alloying elements of bulk Al 2024 do not contribute to cathode performance. The plasma oxidation process of Hochuli improves cathode performance by cleaning the surface and optimizing the oxide film for maximum efficiency. There appears to be a trade-off between life and electron tunneling efficiency for optimum oxide thickness. Auger electron spectroscopy, ellipsometry, and scanning electron microscopy are the techniques used for surface characterization.

HeNe Parallel Plate Laser Development

“…The Al cathode, its less than 10^^-mm oxide film, and changes observed during processing are discussed [15]. Optical concerns associated with hard sealed Brewster windows are presented in a second [19].…”

“…The development of the thin film cathode for use in the parallel plate laser is discussed in a complementary paper by Chance et al [15]. The plasma oxidation process of Hochuli et al [16,17] was found to clean organic contaminants from the cathode surface.…”

“…Cathodes for HeNe lasers is the subject of a complementary paper [15]. Long lifetimes (thousands of hours) have been shown for optimized cathode material and chamber geometry.…”

Influence of surface oxidation on the structure and properties of cold metal cathodes

“…From a wide variety of the suggested materials [4], preference was given to aluminum and its alloys [5][6][7], and miniaturization of helium-neon lasers predetermined the application of beryllium as a material for cold cathodes alongside with aluminum and its alloys [8][9][10][11][12][13][14][15]. At present, special attention is given to the methods of producing oxide films on the aluminum and beryllium surfaces and optimizing their thickness.…”