Optical micro-manipulation based on spatial modulation of optical fields

Optical tweezers has become a powerful tool for research in life science and colloidal physics since its invention due to its advantages of mechanical contact-free and high-precision manipulation of micro-sized particles. However, the conventional single-trap optical tweezers is limited in the increasing demands of research. In recent years, the technique of spatial modulation of optical fields, which modulates the amplitude, phase and polarization state of light, has extensively enhanced the function of optical micro-manipulation, and promoted the advance in laser micro/nano fabricaton, optical sorting and transportation of micro-particles, and colloidal particles studies. The advance in spatial modulation of optical fields to date and their applications in optical micro-manipulation is reviewed, including the holographic optical tweezers, special-mode optical beams manipulation, and vector beams manipulation.