The Key Technology Research Of Optical Trapping Sensing Unit On The Chip

Optical levitating particle technology as one of the measurement methods of high-precision mechanics currently available to mankind with its high sensitivity,strong anti-electromagnetic interference and other advantages,has a unique advantage in high-precision mechanical sensing.The optical accelerometer technology based on optical trapping technology can also overcome the error brought by the rigid connecting in traditional optical accelerometers and is more compact than the cold atomic interferometry technology and is expected to achieve ng-level accuracy.Therefore,the development of light force accelerometer is of great significance to achieve high-sensitivity and high-precision acceleration measurement.In order to meet the practical needs of light force accelerometer,this paper presents a new type of air fiber optical trapping acceleration sensing unit.We combine fiber optical trapping technology and acceleration measurement technology to make use of the advantages of fiber optical trapping system such as modularization and good stability.We are also continuously exploring the problem of reproducible launching and trapping of single particle in the sensing unit,and are devoted to solving the problems of practical application,miniaturization and integration of the optical trapping acceleration sensing unit.First of all,based on the light mechanics and theory of light trapping force,the principle of light levitating particle is explained.The principle and scheme of acceleration sensing based on dual fiber optical trapping are introduced.On this basis,according to the requirements of light force accelerometer,the key technologies and research status of optical trapping sensing unit on chip are analyzed in detail.Then,the on-chip optical trapping sensing unit is simulated and parameterized,including the light source,particles,optical alignment error and so on,and its initial trapping range is simulated.According to the simulation results,three different sensing cell structures were designed and fabricated to achieve fiber alignment accuracy within ± 6pm.Accurate loading of 1 to 5 particles with a diameter of 10?m in a closed sensing cell was achieved by using a tapering probe.Piezoelectric ceramics enable repeated launching of single particle.Finally,the initial capture of the on-chip optical trapping sensing unit is experimentally analyzed and the static stability of the system is tested.In this paper,the use of piezoelectric ceramic vibration can attain one hundred percent of the particle emission efficiency,and the sealed capillary sensing unit structure can realize the goal of miniaturization and integration of sensor unit,and can achieve 5%of the particle capture efficiency,which lays the foundation for practical light force accelerometers.