Abstract
Enabled by multiple optical traps, holographic optical tweezers can manipulate multiple particles in parallel flexibly. Spatial light modulators are widely used in holographic optical tweezers, in which Gaussian point (GP) trap arrays or special mode optical trap arrays including optical vortex (OV) arrays, perfect vortex (PV) arrays, and Airy beam arrays, etc., can be generated by addressing various phase holograms. However, the optical traps in these arrays are almost all of the same type. Here, we propose a new method for generating a hybrid optical trap array (HOTA), where optical traps such as GPs, OVs, PVs, and Airy beams in the focal plane are combined arbitrarily. Also, the axial position and peak intensity of each them can be adjusted independently. The energy efficiency of this method is theoretically studied, while different micro-manipulations on multiple particles have been realized with the support of HOTA experimentally. The proposed method expands holographic optical tweezers’ capabilities and provides a new possibility of multi-functional optical micro-manipulation.
Highlights
Since the pioneering works of Ashkin [1, 2], optical tweezers have become a non-invasive technology for manipulating micro/nano particles
We propose using the phase-only liquid crystal Spatial light modulators (SLMs) to generate a hybrid optical trap array (HOTA), in which arbitrary combinations of optical traps such as Gaussian point (GP), optical vortex (OV), perfect vortex (PV), and Airy beams appear in the focal plane simultaneously
We studied the improvement of energy efficiency with the number of iterations, the movement of the axial position of the optical trap, and the change of peak intensity
Summary
Since the pioneering works of Ashkin [1, 2], optical tweezers have become a non-invasive technology for manipulating micro/nano particles. SLMs use computer-generated-holograms (CGHs) to flexibly shape the wavefront of the laser beam, generating Gaussian point (GP) trap arrays or arrays of special optical modes, such as optical vortex (OV), perfect vortex (PV), and Airy beam. These are essential for a range of applications, including beam shaping, multi-beam laser processing, and optical micro-manipulation [14,15,16,17]. Some unique methods were used to generate multifocal arrays, such as using fractional Talbot effect [24], two-dimensional (2D)
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