Coherent properties of a copper vapor laser and dynamic holograms in vanadium dioxide films

Dynamic holography in vanadium dioxide films was used to study experimentally the coherence of the radiation emitted from a copper vapor laser. It was established that the temporal coherence length exceeded 12 cm and the spatial coherence length was at least equal to the laser beam diameter. An investigation was made of the holographic characteristics of vanadium dioxide using the copper vapor laser to record and reconstruct holograms. The investigation included the dependence of the diffraction efficiency on the power of the laser pulses and their repetition frequency. The possibility of optical modulation of the semiconductor–metal phase transition and of the corresponding recording and erasure of holograms in VO₂ at frequencies above 10 kHz was demonstrated for the first time. There was no deterioration in the holographic characteristics of VO₂ after more than 10⁸ recording–erasure cycles.