Theory of energy gain in a laser-amplifier based on a photon-branched chain reaction: Auto-wave amplification mode under the condition of input signal focusing

Huge energy gain is detected theoretically in a pulsed chemical laser ampli fier based on a photon-branched chain reaction initiating in a gaseous disp erse medium composed of H-2-F-2-O-2-He and Al particles by focused external infrared radiation. It is shown that this effect is observed due to the po ssibility of the ignition of the laser-chemical reaction into an initial sm all focal volume of an active medium. It then spreads out of this minimal v olume spontaneously in the auto-wave regime without external power sources and subsequently fills the whole volume of the laser cavity with a high int ensive electromagnetic field as self-supporting cylindrical photon-branchin g zones formed by the paths of the rays inside the unstable telescopic cavi ty. Calculations show that the ignition of an auto-wave photon-branched cha in reaction under the condition of external signal focusing strongly reduce s the input pulse energy necessary for initiation up to similar to 10(-8) J , and thereby allows a huge value of the energy gain of similar to 10(11). The observed effect of this huge laser energy gain makes it possible to con struct a self-contained laser with kilojoule output energy, which can be in itiated by a very weak source signal. (C) 2000 American Institute of Physic s. [S0021-8979(00)09019-8].