ABSTRACT
Chemical lasers are devices in which chemical energy is directly converted to a population inversion producing laser radiation. (This definition excludes the gas dynamic laser since its population inversion arises from flow expansion rather than directly from a chemical reaction.) The most important types of high-power chemical lasers today are deuterium fluoride (DF) with output near 4 μm wavelength, hydrogen fluoride (HF) near 2.9 μm, and the photochemical iodine laser at 1.3 μm. The HF and DF lasers will be emphasized in this discussion, since the iodine laser is covered elsewhere in the book.
Among high-power gas lasers, chemical lasers possess a number of unique features: (i) the highest output power available in the 2–5 μm region; (ii) little or no electrical input power required; (iii) high efficiency in conversion of energy to laser output. After giving a brief survey of the various types of chemical lasers, the kinetics of the HF/DF devices will be described in some detail, using the best available values for reaction and relaxation rates. The physics of laser operation will be discussed for two particularly important devices: the combustion-driven CW DF laser, and the electron-beam initiated short-pulse HF laser. Scaling laws and critical design areas for these devices will be explained. The present performance status of both CW and pulsed chemical lasers will be compared with other available high-power laser devices.
