Focused CO2 Laser Research Articles

Temporal evolution of the electron density in high-pressure electron-beam-excited xenon plasmas

Measurements of the free-free absorption coefficient in high-pressure (50–400 psia) e-beam-excited rare-gas plasmas have been used to deduce the temporal evolution of electron density in these systems. The measurements were carried out using a focused CO2 laser beam passing through the excited region of the plasma. Comparison of theory and experiment in the early afterglow, where Penning ionization of excimers dominates the electron production, yields a room-temperature rate coefficient of 8×10−11 cm3/sec for this process in xenon.

Simple method for adiabatically sampling reactive gaseous systems for mass spectrometric analysis

An understanding of the nature of the chemical processes occuring in dynamic, reactive, gaseous systems, such as hydrocarbon flames and chemical lasers, requires knowledge of the chemical species that actually exist in these systems. This paper reports the design and use of a flow-type reactor tube which is passed through the ion source of a mass spectrometer permitting the components of a reacting gas phase system to be extracted adiabatically through a 10 μ orifice into the ion source for analysis. The procedure for drilling this orifice with a focused CO2 laser is presented, together with data which indicate that the reactive species extracted from a flame zone are representative of those existing within the reactive system.

Erratum: CO2 laser-induced thermionic emission from metals. Direct energy conversion

Electron emission has been observed when tungsten and molybdenum targets are subjected to focussed CO2 laser radiation. The characteristics of thermionic emission for a variety of excitation conditions are reported. The electron temperature is found to be for an incident power of 40 W cw. Direct energy conversion processes are discussed. Short circuit currents of 2–7 μA and open circuit voltages of 0.1–0.4 V have been observed.

CO2 laser-induced thermionic emission from metals. Direct energy conversion

Electron emission has been observed when tungsten and molybdenum targets are subjected to focussed CO2 laser radiation. The characteristics of thermionic emission for a variety of excitation conditions are reported. The electron temperature is found to be [Formula: see text] for an incident power of 40 W cw. Direct energy conversion processes are discussed. Short circuit currents of 2–7 μA and open circuit voltages of 0.1–0.4 V have been observed.

Cutting of thin metal films with a CO 2-gas laser beam

This paper describes experiments concerning the cutting of thin-metal films with a focused CO 2-laser beam. The films used were aluminium and gold evaporated on substrates. The substrates were soft glass, pyrex glass and fused silica. The influence of both beam energy and cutting velocity was investigated. Good agreement was found between experiments and theory. The cutting process is described.