The Preliminary Study Of The Optical Trap With Supercontinuum

Optical trapping is a useful tool for micromanipulation of small particles on the principle of the optomechanical effect.With the advangtages of non-contact and zero damage,it has a wide application in the field of biology,physics and science chemistry.The light source is an important segment of whole optical trapping system.Different from the previous optical tweezers,this paper utilized supercontinuum laser as trapping source to capture and manipulate the microspheres,and explored the relationship of spectral width and optical trapping force field experimentally.First of all,this paper introduced the basic concept,classification and development status of optical trap technique.Then,we tested the performance of the supercontinuum laser used in experiment.In the second part,this paper designed and constructed a supercontinuum single-beam optical trapping system.Through the system,we succeeded to trap and manipulate the polystyrene spheres experimentally,which proved the feasibility of trapping particles with broadband light source.Then,we obtained the stiffness value of supercontinuum single-beam optical trapping system by the thermal motion analysis method.And the influence on stiffness value due to spectral width was also studied in this experience.The experimental results showed that when the spectral width of light source is wider,the stiffness value of single-beam optical trap system is larger.Furthermore,the capture capability of supercontinuum tweezer is stronger than that of single-wavelength optical trap.Lastly,this paper successfully trapped and manipulated microspheres through self-designed double-beam fiber optical trapping system,which was a new breakthrough in the history of the development of optical trapping.By the method of mobiling optical fiber and controlling optic power,we succeeded to manipulate the position of trapped microsphere.By the method of thermal motion analysis,we obtained the stiffness value of 1.4×10^-6N/m when the optic power of trapping light was 28mW.Meanwhile,we measured the stiffness under different fiber power with the calibration method of power spectrum fitting,and found out the linear realtion between them.Experimental results showed that the stiffness value of supercontinuum optical fiber optical trap is higher than that of the single-wavelength optical trap under the same experimental condition.