D - Centers in intracenter Si:P lasers

ArticleinJournal of Applied Physics 97(11):113708 - 113708-6 · July 2005with3 Reads
Impact Factor: 2.18 · DOI: 10.1063/1.1922091 · Source: IEEE Xplore


    The terahertz Si:P laser is based on the 2p<sub>0</sub>→1s(T<sub>2</sub>) transition of neutral phosphorus donors D<sup>0</sup> that are photoionized by radiation from a C O <sub>2</sub> laser. The manifestation of negatively charged D<sup>-</sup> donor centers has been studied. The population of D<sup>-</sup> centers as well as D<sup>0</sup> donor states are calculated and the amplification provided by D<sup>0</sup> centers is compared with the absorption by D<sup>-</sup> centers. The small signal gain and laser threshold have been measured for a set of Si:P lasers with different degrees of compensation (doping by neutron transmutation). It is shown that absorption by D<sup>-</sup> centers terminates the laser action in Si:P lasers with small compensation (K≪1%) for pump intensities less than 1 kW cm <sup>-2</sup> . At higher excitation levels (≫10 kW cm <sup>-2</sup>) , or for larger compensation, absorption by D<sup>-</sup> centers becomes negligible.