Multiphoton-Injected Plasmas in InSb

Electron-hole plasmas injected in InSb by irradiation with an intense C${\mathrm{O}}_2$ laser beam are studied. These plasmas result from multiphoton production of electron-hole pairs in pure InSb samples. The density, homogeneity, recombination radiation, and conductivity of these injected plasmas were observed at 77 and 4.2°K in external magnetic fields from 0 to 55 kOe. It is found that homogeneous plasma densities of ${10}^{15}$ ${\mathrm{cm}}^{-3\mathrm{}}$ can be produced over a 1-mm cube. Possible mechanisms for plasma lifetimes are discussed. Interesting properties and applications of the multiphoton-injected plasma are suggested.