Observation of erasable holographic gratings at room temperature in Eu^3+-doped glasses

The characteristics of four-wave mixing signals were studied in Eu(3+)-doped glasses. When the Eu(3+) ions were resonantly excited, two types of laser-induced grating were formed: a transient population grating associated with the excited Eu(3+) ions and a holographic grating, which was permanent at room temperature but could be erased either thermally or optically.