拉盖尔-高斯光束光镊捕获性质

Trapping Properties of the Laguerre-Gaussian Beams Optical Tweezers

利用 T 矩阵法研究光镊中微粒大小与入射光束波长相近时，光镊捕获效率与入射光束的阶数、微粒的折射率和尺寸大小的关系．对拉盖尔-高斯光束光镊和高斯光束光镊的轴向和横向捕获效率进行比较．计算结果表明：不同阶数的拉盖尔-高斯光束对微粒捕获效率的影响不同，阶数不超过4的拉盖尔-高斯光束的捕获效率高；微粒半径增加时，拉盖尔-高斯光束的轴向捕获效率逐渐增大，且捕获域也增加，高斯光束的最大捕获效率基本保持不变但捕获域逐渐增大；微粒折射率增加时，拉盖尔-高斯光束和高斯光束的轴向和横向捕获效率均先增加后递减，捕获效率出现了一个峰值，微粒折射率约在1．39～1．69是稳定捕获的最佳数值．

The relationship between optical tweezers trapping efficiency and the orders of the Languerre-Gaussian beams （LG beams）,the refractive index and the size of the particles were studied by using T-matrix method.The axial and radial trapping efficiency of optical tweezers of the LG beams and that of the TEM00-mode Gaussian beams were compared.The results show that the trapping efficiency was influenced by the orders of the LG beams.The axial trapping efficiency of the LG beams with orders less than 4 are higher than that of the LG beams with orders more than 4.The axial trapping efficiency and the trapping regions of the LG beams increased with increasing of the particles radii,meanwhile,the axial trapping efficiency of the Gaussian beams almost keeps constant,but the trapping regions increased gradually.The axial and radial efficiency of optical tweezers of the LG beams and the TEM00-mode Gaussian beams increased first and then decreased,with increasing of the refractive indices of the particles,and the trapping efficiency has a peak.The particles with refractive indices between 1.39 and 1.69 were stably trapped.