Optical tweezers play an important role in many domains, especially in life science. And optical gradient force is necessary for constructing optical tweezers. In this paper, the optical gradient force in the focal re...Optical tweezers play an important role in many domains, especially in life science. And optical gradient force is necessary for constructing optical tweezers. In this paper, the optical gradient force in the focal region of radial varying polarization Bessel- Gauss beam is investigated numerically by means of vector diffraction theory. Results show that the beam parameter and vary rate parameter that indicates the change speed of polarization rotation angle affect the optical gradient force pattern very considerably, and some novel force distributions may come into being, such as multiple force minimums, force ring, and force crust. Therefore, the focusing of radial varying polarization Bessel-Gauss beam can be used to construct optical traps.展开更多
Optical vortex has attracted much interest re-cently due to its novel properties and applica-tions. In this paper, the focusing properties of Gaussian beam containing one non-spiral opti-cal vortex are investigated by...Optical vortex has attracted much interest re-cently due to its novel properties and applica-tions. In this paper, the focusing properties of Gaussian beam containing one non-spiral opti-cal vortex are investigated by means of scalar diffraction theory. Simulation results show that topological charge of non-spiral optical vortex affects optical intensity distribution in focal re-gion considerably, and non-spiral focal pattern may also occur. Multiple intensity peaks may appear companying with center main focal spot under condition of higher topological charge. In addition, the number of weak intensity peak outside of the center main intensity peak is re-lated to the value of topological charge.展开更多
Focal shift of radially polarized Bessel-modu- lated Gaussian (QBG) beam by phase shifting is investigated theoretically by vector diffraction theory. The phase shifting distribution is the function of the radial coor...Focal shift of radially polarized Bessel-modu- lated Gaussian (QBG) beam by phase shifting is investigated theoretically by vector diffraction theory. The phase shifting distribution is the function of the radial coordinate. Calculation results show that intensity distribution in focal region can be altered considerably by the topo- logical charge of QBG beam and the phase pa-rameter that indicates the vary degree of the phase shifting along radial coordinate. Topolo- gical charge induces the focal shift in trans-verse direction, while phase parameter leads to the focal shift along optical axis of the focusing system. More interesting, the focal shift may be incontinuous in certain case.展开更多
文摘Optical tweezers play an important role in many domains, especially in life science. And optical gradient force is necessary for constructing optical tweezers. In this paper, the optical gradient force in the focal region of radial varying polarization Bessel- Gauss beam is investigated numerically by means of vector diffraction theory. Results show that the beam parameter and vary rate parameter that indicates the change speed of polarization rotation angle affect the optical gradient force pattern very considerably, and some novel force distributions may come into being, such as multiple force minimums, force ring, and force crust. Therefore, the focusing of radial varying polarization Bessel-Gauss beam can be used to construct optical traps.
文摘Optical vortex has attracted much interest re-cently due to its novel properties and applica-tions. In this paper, the focusing properties of Gaussian beam containing one non-spiral opti-cal vortex are investigated by means of scalar diffraction theory. Simulation results show that topological charge of non-spiral optical vortex affects optical intensity distribution in focal re-gion considerably, and non-spiral focal pattern may also occur. Multiple intensity peaks may appear companying with center main focal spot under condition of higher topological charge. In addition, the number of weak intensity peak outside of the center main intensity peak is re-lated to the value of topological charge.
文摘Focal shift of radially polarized Bessel-modu- lated Gaussian (QBG) beam by phase shifting is investigated theoretically by vector diffraction theory. The phase shifting distribution is the function of the radial coordinate. Calculation results show that intensity distribution in focal region can be altered considerably by the topo- logical charge of QBG beam and the phase pa-rameter that indicates the vary degree of the phase shifting along radial coordinate. Topolo- gical charge induces the focal shift in trans-verse direction, while phase parameter leads to the focal shift along optical axis of the focusing system. More interesting, the focal shift may be incontinuous in certain case.
