石墨烯光推进原理分析及光驱动特性测试研究

Analysis on graphene optical propulsion theory and measurement of its optical driving characteristics

光推进是将光能转换为动能的一种推进方式,石墨烯材料具有独特的光电特性,为光推进技术发展提供了重要前提。文章介绍了石墨烯光推进技术发展,讨论了石墨烯光推进的电子射流、Knudsen力、激光烧蚀三种作用机理假设,分别计算了电子射流及Knudsen力产生推力的数量级,认为Knudsen力更有可能是光产生驱动现象的原因。针对Knudsen力这一假设,采用悬丝摆动的微小力测量方法,表征了石墨烯海绵表面受激光照射一侧和未被照射一侧的表面温度,两侧表面形成了显著的温差,热量主要在受照射的一侧表面聚集;讨论了真空度等参数对光驱动力大小产生的影响。结果表明,石墨烯光驱动力在微牛量级,低真空度(1~10 Pa)是产生光驱动力的适宜环境,热效应在光驱动里中占据主导作用,间接表明了石墨烯光驱动力主要来自于Knudsen力的可能性。

Optical propulsion is a propulsion method that converts light energy into kinetic energy.Graphene has unique optoe-lectronic properties,which is an essential prerequisite for developing optical propulsion technology.The development of graphene optical propulsion technology was introduced.Three kinds of mechanisms of graphene photo propulsion were dislussed,such as elec-tron jet,Knudsen force,and laser ablation.Moreover,the order of the driving force generated by the electron jet and the Knudsen force was calculated.It is believed that Knudsen force is more likely to be the cause of light driving phenomenon.In this paper,the surface temperature of the graphene sponge under laser irradiation on one side and the unirradiated side was characterizd by using a small force measurement method of a suspended wire swing.The noticeable temperature difference was formed between the two sur-faces,and heat was mainly concentrated on the irradiated surface.The influence of vacuum degree on the magnitude of the optical driving force was discussed.The results show that the photo-driving force of graphene is in the micro-newton order.Thermal effect plays a dominant role in optical driving force.When the laser irradiation power is constant,a low vacuum degree(1~10 Pa)is a suitable environment for generating the photo-driving force,which indirectly indicates the possibility that the photo-driving force of graphene mainly comes from the Knudsen force.