Study On Laser Protective Vanadium Dioxide Thin Film

With the rapid development of the laser technology,laser blinding weapons have come into being,a type of soft-kill tactical weapon,which will give rise to the signal interference of photoelectric system,even the damage to the photoelectric detection equipment.Therefore,it is of major significance to explore and search the material of laser protection.The vanadium dioxide is a type of material of the reversible phase transition from the semiconductor-metal phase to metal phase and endowed with the property of the thermal and photo-induced phase transition,excellent modulation effect on the infrared spectrum,the low phase change threshold,the high damage threshold and the short phase change response time,which have met the requirements of laser protection.This paper has focused on the switching effect of vanadium dioxide on high-energy infrared laser?>90%?and the improvement of low-temperature light transmittance of weak infrared signal?>80%?.The research contents are mainly as following:?1?The basic structure and phase transition theory of VO₂ have been described in detail,and the optical constants of VO₂ have been calculated based on the Drude model,which provides a theoretical basis for the subsequent simulation design and preparation experiments of the film system.?2?The VO₂/MgF₂ bilayer system antireflection film system have been designed by using TFCalc optical film system software and antireflection film theory.Based on the equivalent medium theory,the VO₂-MgF₂ thin film of the nano-hole structure has been designed and simulated with the characteristics of the high infrared transmittance and high switching rate.?3?The two-step method of reactive ion beam sputtering and post-annealing process has been utilized to fabricate the VO₂ thin films.The VO₂ thin films with high infrared transmittance at low temperature was obtained.A layer of MgF₂ antireflection film was deposited on VO₂ thin films by RF magnetron sputtering,to achieve the high low-temperature infrared light transmittance and high switching rate.?4?The phase transition thresholds and optical switching rates of the different VO₂ films were measured by using different wavelength lasers.Moreover,the phase transition response time of the films was preliminarily explored.A silicon photocell was used to verify the laser protection effect of the VO₂ film.