Atmospheric-Pressure Pulsed CO2 Laser Utilizing Preionization by High-Energy Electrons

Abstract

An atmospheric-pressure pulsed CO2 laser is described in which the gas is preionized by the injection of high-energy electrons into the laser volume. These electrons are derived from a high-voltage (120-kV) glow discharge surrounding the laser. The preionization achieved has allowed 300 J to be delivered to 1. 7 liter of gas in a single discharge without the development of arcs, irrespective of whether the gas contained helium. The highest output energy (20 J) was obtained with a mixture of CO2, N2, and He in the proportions 3 : 3 : 4 by volume.

Electron-beam pumping of visible and ultraviolet gas lasers

“…These guns have taken the form of diodes with solid cathodes ((>2) or hollow cathodes (03) with grid control (64). However, such guns have only recently been applied to laser pumping (65).…”

Properties of a coaxial cw CO_2 laser

“…Such a decrease is to be expected eventually due to the increase of temperature with pressure in the positive column.' 3 For most of our experiments, the discharge is operated at about 5 Torr. At higher pressure, the discharge tends to contract to the cathode surface.…”

“…Once an arc is formed, the lasing action is terminated, and this is the main problem which has to be overcome for all transversely excited lasers. A coaxial discharge for the laser gain medium has been successful for pulsed CO 2 lasers, 3 - 5 and a study of the gain medium of a coaxial discharge for cw CO 2 lasers has been performed. 6 The purpose of this work has been to develop a coaxial discharge scheme for generating a gain medium and to study the application of this medium to a coaxial cw CO 2 laser oscillator.…”

Some experimental studies on the UV spark pin-array pre-ionization in TEA CO2 laser

“…These lasers provide output pulses in 9-11 µm spectral range with energies up to several kJ [1,2], time durations varying from ps [3] to µs [4] orders and repetition rates up to several kHz [5] with relatively low costs and without the needs for high-tech facilities. This flexibility in output characteristics are due to novel developments and progresses in various aspects including discharge circuits [6-8], electrodes [9-12] and resonator [13, 14] configurations, gas mixture [15][16][17] and pressure [18][19][20], pulse shaping techniques [21] as well as pre-ionization methods [22][23][24][25][26]. Each of these items plays a key role in achieving stable and longterm operation of the laser especially at high repetition rates and sealed-off regime [27][28][29].…”