The family of lasers: a survey

Operating over a frequency range from audio to ultraviolet, the modern laser may be the most widely applicable active device at the disposal of today´s engineer, enabling him to generate, amplify, modulate, transmit, and detect signals at frequencies more than 10000 times higher than was previously possible. Yet despite the almost unlimited potential for new and exotic applications offered by these shorter wavelengths, innovations have not lived up to their rave notices. Reasons for this relative inertia vary according to the application intended but, in general, it can be predicted that progress in the laser art will accelerate with the improvement of laser efficiency, development of auxiliary systems, and an updating of engineering thinking in terms of finding the ``problems´´ that lasers can solve. This first article in a series deals with the laser devices themselves¿their advantages and their deficiencies¿and will summarize what is happening in the laser art today. Other parts, scheduled to appear in future issues of IEEE SPECTRUM, will cover applications in materials processing, instrumentation and measurement, optical communication, medicine, holography, data processing and storage, displays, and safety.