Research On Transmission Characteristics Of High-order Cylindrical Vector Light Field

The polarization state is one of the most fundamental properties of electromagnetic field. High-order cylindrical vector beam has spatially nonuniform polarization, which has potential applications in optical tweezers, micromachining technology, remote sensing and free-space optical(FSO) communications. Therefore, study on the propagation characteristics of high-order cylindrical vector beam can lay the foundation for the FSO communications especially in the free-space and the atmospheric turbulence. In this paper, the propagation characteristics of high-order cylindrical vector beam under the off-axis condition in the free-space and the propagation characteristics of high-order cylindrical vector beam in the atmospheric turbulence has been investigated theoretically and numerically. The main innovation points are listed as follows:1. The analytic expressions of the electric field and the intensity after OHCVB propagating in free-space are derived. The impact of the off-axis situation on the propagation characteristics of the off-axis high-order cylindrical vector beam(OHCVB) is theoretically studied. The result shows that the intensity tends to a stable energy distribution finally. With the increase of the topological charge, the energy shifts from x-axis to y-axis, so the annular beam is broken into two parts along the y-axis direction. Due to the off-axis situation often occurs in the generation of vector light field, the results can guide the calibration of the high-order cylindrical vector beam in practice, and they can also help us to understand the dynamic propagation characteristics of the vector beam under the off-axis condition.2. The analytic expressions of the intensity and degree of polarization after PCHCVB propagating in the atmospheric turbulence are derived. The propagation characteristics of partially coherent high-order cylindrical vector beam (PCHCVB) propagating in a turbulent atmosphere are theoretically investigated. Numerical results indicate that the intensity distribution and the polarization distribution of the beam are affected by propagation distance, the structure constant, the transverse coherence length and the topological charge. The larger the value of the topological charge is, the slower the beam profile will degenerate. And with the increase of the topological charge, PCHCVB can effectively mitigate level of scintillation caused by atmospheric turbulence.