Optical Tweezers with Assistance of Sub-Microsecond-Duration Pulse Laser Beam

Abstract

We report optical tweezers with the assistance of a strong instantaneous force generated by a focused pulse laser beam of sub-microsecond duration. A strong instantaneous force is required in biological applications. A suitable pulse duration for pulse assistance in water is derived on the order of 100 to 1000 ns from motion analysis of a micrometer-sized particle. We performed optical tweezers experiments with a focused pulse beam of 160 ns duration coaxially incident with a CW laser beam. From the experiments on particle extraction from a glass surface, the required energy for extraction is smaller than the case of 150 µs duration by a factor of 60.

Launch and capture of a single particle in a pulse-laser-assisted dual-beam fiber-optic trap

“…This could explain the fact that although the peak power is decreasing, the detachment threshold increases sharply with the pulse duration, which has been experimentally verified by Saki Maeda and Tadao Sugiura [28].…”

“…Pulsed-laser has been widely used in the field of laser cleaning, which produces a strong lifting force that could overcome adhesion forces and gravity to remove the particles quickly and efficiently [23][24][25] without considering the laser-induced damage to the particles. Moreover, pulse-laser-assisted optical tweezers (PLAT) open the possibility of manipulating stuck microparticles in aqueous environments and may find broad applications in cell biology and molecular biology [26][27][28]. Rapid loading and manipulation of a microsphere in air or vacuum remains challenge until now.…”

Manipulation and measurement by optical tweezers on a cell

“…This limitation is one of major problems in actual application of optical tweezers. To expand this limitation we invent a pulse laser assisted optical tweezers [1], which enables us to generate strong instantaneous force by condensed laser energy within a pulse duration. Figure 1 shows a schematic of optical tweezers.…”

Transfer characteristics for laser-induced forward transfer of stainless steel particle

“…Optical trapping (OT) is also a means of moving powders using a laser. [13][14][15][16] In this technique, the powder is attached to the substrate by the van der Waals force and is moved to the desired position using the radiation pressure of incident light.…”

“…11,12,[19][20][21][22][23] There are reports of OT processes being used with particle sizes of 2 μm or less. [13][14][15][16] The particle LIFT method has been used for polymers with particle diameters of 30 to 40 μm. 17,18 To render such a method applicable to AM, it is necessary to transfer metal powders with a particle size of several tens of millimeters (Fig.…”