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Keywords:

  • ZnS(Se):Cr;
  • thin films;
  • waveguide structures;
  • fabrication;
  • characterization;
  • lasing;
  • electrical pumping;
  • impact excitation mechanism

ZnS:Cr and ZnSe:Cr are the focus of studies as media for broadly tunable optically pumped lasers operating in the near- and mid-IR regions. It is of great interest to obtain such lasers electrically pumped. The effective electrical excitation of Cr2+ ions was demonstrated only in the case of the impact mechanism for thin-film structures with insulator layers between an electroluminescent film and electrodes, which prevent avalanche breakdown at high electric field (≥ 1 MV/cm). To obtain lasing, the waveguide electroluminescent structures were used. For the first time, the stimulated emission and the laser oscillation were demonstrated in the ZnS:Cr waveguide structures. Although the lasing is unstable as yet, these results lay the foundations of a new direction in laser physics aimed at creation of electrically pumped lasers by dint of impact excitation. Published results concerning various aspects of ZnS:Cr and ZnSe:Cr thin films and waveguide structures as promising electrically pumped laser media are reviewed. The causes of the instability of the laser oscillation and means of improving their characteristics are also considered.