Realization And Mechanism Of Laser-driven Macro-carbon Materials

Manipulating objects with light has many advantages,such as non-contact,remote and pollution-free.Most of these methods are performed in a liquid environment.The most common way is to use the radiation pressure and potential energy of light itself,such as optical tweezers.However,the forces generated by radiation pressure and potential are so weak that only micro-nano scale objects can be manipulated.In recent years,the lightmatter interaction has been modified to extract a response from the medium to extend the range of optical manipulation to microscopic scale,such as the photo-thermophoresis,where a temperature gradient is caused by the photothermal effect of the objects itself,or the photo-electrophoresis effect,where the object induces a charge gradient.These methods allow people to manipulate micron-scale objects.However,due to the inherent properties of liquids,it is very difficult to manipulate large objects of centimeters order and above and to increase their speed.So researchers began looking again for ways to manipulate objects in a gaseous environment,a process that dates back to the Crooks radiometer.In recent years,researchers have realized the driving of microspheres and multilayer GO slices in a gas environment,but the spatial scale of these working objects and motions is still in microns.So far,the researchers have managed to spin millimetersized micro-motors by using optical driving,but the direction of rotation is still out of control.Therefore,achieving accurate manipulation of objects with greater degrees of freedom and above centimeter scale by using light remains a great challenge.In this thesis,a method of using laser to accurately control the movement of macroscopic carbon materials is proposed.And the rotation and long range linear motion of magnetic levitation graphene ship is successfully controlled.The specific work is as follows:I first investigated whether different types of macroscopic carbon materials can be induced to move in high vacuum by laser.On this basis,a simple method to prepare graphene flakes was proposed for the preparation of graphene ships.Then two unique graphene ships were designed based on the magnetic flux distribution of the magnetic trace,and the graphene ships were controlled to rotate and move horizontally above the magnetic trace by laser.The rotation and velocity of motion under different conditions were studied.The observed data was analyzed and interpreted according to thermodynamics and aerodynamics.I have clarified the source of driving force and puts forward several strategies to improve driving force.In this thesis,I successfully used laser to control the macro maglev graphene ship rotating in different directions and moving smoothly and linearly over a long distance above the magnetic orbit,providing a better method for laser accurate manipulation of large objects.It is found that the speed of rotation and linear motion can reach 170 rpm and 55 mm/s at 150 m W,which means it is possible to develop a new type of rapid transit system and light-energy conversion system.