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This article describes the x-ray lasers in plasmas, only. The plasma x-ray lasers rely on stimulated emission to generate or amplify coherent, directional, high-brightness electromagnetic radiation in the near X-ray or extreme ultraviolet region of the spectrum, that is, usually from ~3 nanometers to several tens of nanometers (nm) wavelength.
The enhancement of the brightness compared to the unfocused output from the bomb is /, where is the efficiency of conversion from bomb X-rays to laser X-rays, and is the dispersion angle. [ 117 ] If a typical ICBM is 1 metre (3 ft 3 in) in diameter, at a distance of 1,000 kilometers (620 mi) represents a solid angle of 10 −12 steradian (sr).
Laser types with distinct laser lines are shown above the wavelength bar, while below are shown lasers that can emit in a wavelength range. The height of the lines and bars gives an indication of the maximal power/pulse energy commercially available, while the color codifies the type of laser material (see the figure description for details).
By 1980 Livermore considered both nuclear bombs and nuclear reactors as viable energy sources for an x-ray laser. On November 14, 1980, the first successful test of the bomb-powered x-ray laser was conducted. The use of a bomb was initially supported over that of the reactor driven laser because it delivered a more intense beam.
Sankey diagram of the laser energy to hohlraum x-ray to target capsule energy coupling efficiency. Note the "laser energy" is after conversion to UV, which loses about 50% of the original IR power. The conversion of x-ray heat to energy in the fuel loses another 90% – of the 1.9 MJ of laser light, only about 10 kJ ends up in the fuel itself.
A disk laser configuration presented in 1992 at the SPIE conference. [1] One type of solid-state laser designed for good power scaling is the disk laser (or "active mirror" [1]). Such lasers are believed to be scalable to a power of several kilowatts from a single active element in continuous-wave operation. [2]
Laser pumping is the act of energy transfer from an external source into the gain medium of a laser. The energy is absorbed in the medium, producing excited states in its atoms. When for a period of time the number of particles in one excited state exceeds the number of particles in the ground state or a less-excited state, population inversion ...
The active laser medium (also called a gain medium or lasing medium) is the source of optical gain within a laser. The gain results from the stimulated emission of photons through electronic or molecular transitions to a lower energy state from a higher energy state previously populated by a pump source. Examples of active laser media include: