Luminescence of rock salt in very strong electric fields

The luminescence of thin single-crystal layers of NaCl in very strong electric fields was observed. Oscillograms of the brightness waves were obtained. The light flux and luminescence delay were measured as functions of the applied field strength amplitude. The reasons for the delay phenomenon and the drop in the electric strength of samples when electrodes with electron conductivity (metal or graphite) are used are discussed.The authors sincerely thank Prof. G. A. Vorob'ev for his guidance and P. E. Ramazanov for valuable observations.