使用聚焦部分相干高斯谢尔涡旋光束, 对不同折射率的瑞利粒子的辐射力做了分析, 着重研究了相关长度和束腰宽度对辐射力和俘获稳定性的影响。结果表明: 相关长度和束腰宽度分别存在临界值, 相干长度小于等于其临界值或束腰宽度大于等于其临界值时, 可利用其俘获相对折射率大于1的微粒; 而在相关长度大于其临界值或束腰宽度小于其临界值时, 可利用其俘获相对折射率小于1的微粒。对俘获稳定性的分析表明, 需选择适当的相关长度和束腰宽度才能稳定俘获瑞利粒子。

Radiation forces of a focused partially coherent Gaussian Schell-model (GSM) vortex beam used to trap Rayleigh dielectric spherical particles with different refractive indices are analyzed, where the dependence of radiation forces and trapping stability on the correlation length and waist width is stressed and illustrated by numerical examples. There exist critical values for the correlation length and waist width of the GSM vortex beam. The particles with relative refractive index larger than one can be trapped by the beam with waist width less than critical width or correlation length larger than critical length, while the particle with relative refractive index less than one can be trapped by the beam with waist width larger than critical width or correlation length less than critical length. The stability analysis indicates that, by a suitable choice of the correlation length and waist width, stable trapping can be achieved for Rayleigh particles with different refractive indices.