Observation of persistent spectral hole burning in CuBr quantum dots

Persistent spectral hole-burning phenomenon in CuBr quantum dots embedded in glass was observed. The spectral hole and the sideband holes were made together with the redshift of the absorption spectrum in proportion to the logarithm of the laser fluence and were preserved for more than 8 h at 2 K. They were erasable by the temperature rise or by the light exposure. Electron trapping at the surface of the dots and hole tunneling into traps in the glass host is the most probable origin of the persistent spectral hole-burning phenomenon in CuBr quantum dots.