Plasma Science: From Fundamental Research to Technological Applications (1995)
Chapter: GAS DISCHARGE LASERS
and non-LTE low-temperature plasmas, sophisticated diagnostics, and measurement of atomic and molecular cross-section data for electron-impact processes of importance to the lighting industry.
Because industrial R&D goals have become increasingly short-term over the last 10 years, it is important that the academic and government communities initiate longer-term R&D in plasmas related to lighting. Examples of research and development that would be of great benefit to the lighting industry include the application of massive computation techniques to lighting problems and improved diagnostics that will provide detailed information about the behavior of lighting plasmas. New approaches to modeling and probing complex sheaths associated with thermionic electrodes, for example, would help the lighting industry reduce mercury and thorium usage and would also increase lamp efficiency and life. Other important topics include methods to obtain higher conversion efficiency of electrical energy into radiation and the evaluation and exploitation of solid-state sources for lighting applications.
Scientific opportunities in lighting plasmas include the exploration of novel ways of producing monoenergetic or narrow electron-energy distributions in discharges to selectively excite electronic states, resulting in the more efficient production of radiation and the reduction of long-wavelength emission and thereby enhancing visible emission, using the principles of quantum electrodynamics and quantum interference.
Radiation from lamps can have important applications in environmental cleanup and other areas, including water purification with light, promoting algae growth with special metal-halide sources to reduce heavy metal concentrations in water, accelerating food growth, and a variety of display applications.
Lighting plasmas are synergistic with the fields of plasma deposition and etching, materials science, electronics, and lasers. However, increased scientific productivity in this area will require new basic experimental facilities.
GAS DISCHARGE LASERS
The field of gas discharge lasers has had considerable government support over the last 40 years. Strong support in the 1970s and 1980s led to an improved understanding of the basic phenomena in high-pressure plasmas, including electron-impact excitation cross sections of vibrational and electronic excited states, the physics of the stability of high-pressure discharges, and the homogeneous chemistry and products of excited-state reactions. Advances in the understanding of discharge physics include improved understanding and predictive capability of the discharge parameters and the stability of the plasma, discovery of the dominant impact that excited states have on discharge physics and laser chemistry, and an increased knowledge of electronic kinetics and the interaction between secondary electrons and excited states.
This research made significant contributions to advancing the state of the
