Miniature optical force levitation system

Optical levitation technology is a new levitation technology for trapping micro/nano-particles.By taking advantage of the mechanical effect of light,it has the characteristics of non-contact and high sensitivity.However,the traditional optical levitation system is large in volume,complex in adjustment,and greatly affected by the external environment.Herein,a miniature optical levitation system based on a laser diode,miniature lenses,and a micro-electro-mechanical system(MEMS) particles cavity is proposed.First,we analyze the output spot characteristics of the laser diode.Being compared the characteristics of different kinds of laser diodes,the type,wavelength,and power of diodes in the levitation system are determined.Then,the micro-particles cavity is fabricated based on the MEMS process.The MEMS process is widely used in the manufacturing of micro-electronic devices because of its advantages of small size,high precision,and easy mass production.The particle cavity processed in this way can not only ensure the advantage of small volume,but also possesses high processing repeatability.The volume of the entire package including the light source,focusing lenses,and MEMS cavity is just Φ10 mm×33 mm,which is the smallest optical levitation system reported,to the best of our knowledge.After the entire levitation system is designed and set up,one silica particle of 10 μm diameter is stably trapped in the atmospheric environment.Finally,the micro-displacement and vibration signal are detected by a four-quadrant photoelectric detector to evaluate the stiffness of the optical levitation system.