Optical tweezers use the radiation pressure to trap and manipulate the microscopic particles. Using various algorithms multiple traps are being formed which can trap a number of particles simultaneously. In contrast t...Optical tweezers use the radiation pressure to trap and manipulate the microscopic particles. Using various algorithms multiple traps are being formed which can trap a number of particles simultaneously. In contrast to multiple traps, many particles can be trapped at a single trap position. It is known that when two or more particles are trapped in a single trap they align themselves in axial direction and it appears as if only one particle is trapped. We present a study of the dependence of the optical trapping force on the number of particles in a single trap using equipartition method;the study was carried out for particles of different sizes. The trapping force was first found to increase then decrease with number of particles in trap for all particle sizes. We feel that our studies will be useful in applications of optical tweezers involving trapping of multiple particles in a single trap.展开更多
Flow of micro particles and fluids is important in many microscopic systems. Here we present details of our finding of a directional flow of micro particles due to a single beam optical trap. It was found that the dir...Flow of micro particles and fluids is important in many microscopic systems. Here we present details of our finding of a directional flow of micro particles due to a single beam optical trap. It was found that the directional flow depends upon the size of optical trap, the number density of particles in the solution and the time after the trap was created. We suggest controlling the motion of microscopic particles in a fluid by varying a simple parameter like beam size for microfluidics applications.展开更多
文摘Optical tweezers use the radiation pressure to trap and manipulate the microscopic particles. Using various algorithms multiple traps are being formed which can trap a number of particles simultaneously. In contrast to multiple traps, many particles can be trapped at a single trap position. It is known that when two or more particles are trapped in a single trap they align themselves in axial direction and it appears as if only one particle is trapped. We present a study of the dependence of the optical trapping force on the number of particles in a single trap using equipartition method;the study was carried out for particles of different sizes. The trapping force was first found to increase then decrease with number of particles in trap for all particle sizes. We feel that our studies will be useful in applications of optical tweezers involving trapping of multiple particles in a single trap.
文摘Flow of micro particles and fluids is important in many microscopic systems. Here we present details of our finding of a directional flow of micro particles due to a single beam optical trap. It was found that the directional flow depends upon the size of optical trap, the number density of particles in the solution and the time after the trap was created. We suggest controlling the motion of microscopic particles in a fluid by varying a simple parameter like beam size for microfluidics applications.