Luminescence and superfluorescence-like emission from a thin layer of O2− centers in KBr crystal

Abstract Intense directional emission from a thin layer of O 2 − centers introduced in KBr has been investigated under strong excitation in the range of 4.5–80 K. Its temporal and spectral profiles have been measured simultaneously for each excitation shot. It has been found that the emission changes from superfluorescence to amplified spontaneous emission drastically around 20 K.