........ published in NEWSLETTER # 59
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........ published in NEWSLETTER # 59
PULSED METAL VAPOUR LASERS - PHYSICS AND EMERGING APPLICATIONS IN INDUSTRY, MEDICINE AND SCIENCE
by Dr. C.E. Little, University, St. Andrews (U.K.) and Professor N.V. Sabotinov, Institute of Solid State Physics (Bulgaria)
High-power pulsed metal vapour lasers were first demonstrated in the USA in the 1960s, but it wasn't until the mid-seventies that high average output powers of tens of watts were achieved as a result of developments in Russia. The breakthrough that led to high-power laser output signalled the move for major deployments of manpower and funding to develop the technology further and improve the performance of pulsed metal vapour lasers, in particular of copper vapour lasers. The technology has continued to develop to the point where today multiple green/yellow laser beams of more than 1 kilowatt average power each are routinely generated by copper vapour lasers at around 1 % efficiency, 24 hours a day (Lawrence Livermore National Laboratory) for isotope enrichment. They are the highest power visible lasers ever developed.
Metal vapour lasers are now considered to be the enabling technology for a number of important processes. The copper vapour laser offers significant advantages in a number of areas, including very high-precision machining of metals such as copper and aluminium, which are traditionally very difficult materials to process. These lasers can also be used to manufacture high quality thin films of material produced by photoablation. For many applications, the present-day generation of CO2, Nd:YAG and excimer industrial lasers would be better replaced by a new generation of high-power copper vapour lasers, provided long- lived, reliable and easy-to-use devices can be developed in the near future. Other important and emerging applications of metal vapour lasers are to be found in medicine, spectroscopy and astronomy. These applications include diagnostic, therapeutic and forensic medicine, e.g. for cancer photodynamic therapies, removal of haemangiomas (port wine stains) and other psychologically damaging skin abnormalities; the creation of laser guide stars for adaptive optics astronomy; and atomic and molecular spectroscopy for fundamental scientific studies.
With the ending of the Cold War, the most active leading and eminent researchers in the field of high-power metal vapour lasers, from East and West, met in St. Andrews for the first time, under the auspices of NATO. This volume (NATO ASI SERIES 1-5) is an almost complete snapshot of the current understanding of the physics of pulsed metal vapour lasers, and world view of their present and emerging applications. Papers cover the following areas: the early history of pulsed metal vapour lasers; the plasma kinetics and excitation mechanisms of self-terminating and recombination metal vapour lasers; beam quality issues for applications; frequency harmonic generation for mid-UV applications; high-precision processing of metals, ceramics, glasses, and plastics using metal vapour lasers; applications in medicine, including oncology and dermatology; and applications in science such as spectroscopy and mass spectrometry.
The book is a practical source of information on the physics, engineering and applications of metal vapour lasers. It will be of interest to scientists, teachers and graduate researchers working in the fields of gas lasers, laser optics, gas discharges, optoelectronics, and laser applications in industry, science and medicine.
Reference books: 1-5, 3-7, 3-10, E238, E265, E283, E307