Laser technology: Theory and operating principles: Application of the principles of quantum electronics has yielded hundreds of lasers whose wavelengths span from the infrared to the X-ray region of the spectrum

A brief overview is presented of the theory and operation of the laser and its most prominent applications. The treatment covers the new wavelengths that have been obtained by researchers and the methods by which radiation is shifted from a fixed wavelength laser to the desired portion of the spectrum (wavelength conversion). Three of the most efficient and most commonly used techniques for this conversion are discussed. These are stimulated Raman scattering, optical harmonic generation, and the operation of optical parametric oscillators.