Ultrahigh energy gain in small volumes of the active medium in a laser based on an autowave photon-branched chain reaction

The possibility is demonstrated of initiating an autowave photon-branched c hain reaction (PBCR) in an originally small focal volume of the laser activ e medium (H-2-F-2-O-2-He-Al particles) by the external IR radiation focused with a lens. It is shown that the PBCR can spread over the entire active m edium of the laser with an unstable telescopic cavity, in the form of self- sustained cylindrical zones of photon branching. The autowave laser-chemica l reaction initiated in the lens focus strongly reduces the required energy of the initial input pulse to 0.01 muJ, thereby providing a huge energy ga in of similar to 10(11). Because of this ultrahigh gain, a small submicrojo ule laser can be used as a master oscillator.