Smith-purcell Effect In Photonic Crystals

Smith-Purcell free electron laser shortened as SP FEL is an important branch of free electron laser. This article on the Smith-Purcell effect, free electron and the relationship between the location of photonic crystals, photonic crystal structure optimization, the launch of free-electron parameters are more in-depth, comprehensive study, there has been some valuable research results.In this paper, based on Smith-Purcell free-electron laser theory, discuss a new type of free electron laser characteristics. Special discussion of the photonic crystal grating and Smith-Purcell effect, mainly on one-dimensional grating of the Smith-Purcell effect and the theory of Magic formula, compared to simulation data, with further verification from the photonic crystal grating similar to analog comparator, and then study Photonic Crystal Smith-Purcell effect. Photonic crystals change with the rise and, as well as the electron beam direction, so the number of photonic crystals to study the Smith-Purcell effect, in order to find a better model of photonic crystal structure and electron-beam and other relevant parameters are made in the THz band stronger and stronger radiation power. Briefly investigated the Smith-Purcell radiation peak of the photonic crystals and the band structure corresponding.With the help of two-dimensional particle-in-cells simulation, we adopt a flat gating in an open rectangular cavity model to simulate the Smith-Purcell radiation. By setting multitude observe point and observing the bitmap of longitude magnetic field, the frequency of the observe point and space momentum distribution of the beam, simulation for a single bunch is carried out first, from which we can observe the process of generation of SP radiation and the evanescent wave and the difference of them. When the single bunch passes over the grating surface, the SP radiation will be inspired SP. The SP radiation frequency changes with the angle. According to simulation results, the curve that radiation frequency changes with the angle is familiar with the curve draw follow theoretical formula. Then, by observing the bitmap of longitude magnetic field, we simulate a train of periodic bunch to demonstrate the properties of the super-radiant radiation, the output angle of second harmonic and third harmonic frequency are also following the theoretical formula. Comparing the simulation results with the theory, we find they are similar. Then replaced by grating photonic crystal, the design of a wide range of photonic crystal (single-layer, multi-layered, rectangular, triangular), study the shape of photonic crystals and scattering of the SP radiation frequency of wave radiation. Grating and research the same way, the same observation to the SP radiation and scattering, as well as ultra-SP radiation.Study the effect of new type of photonic crystal type of Smith-Purcell free electron laser and the use of two-dimensional particle simulation of a representative cylindrical photonic crystal research. Through research to study two different situations, including different angles of observation window, single-electron and multi-electronic, and photonic crystals with rectangular and triangular comparison of the two structures, design and simulate a variety of different situations photonic crystals to a variety of Smith-Purcell radiation output and make a comparative analysis. Through analysis of simulation results available, the use of the triangle of the photonic crystal grating with multi-electron beam can be fired relatively large power output; and received THz electromagnetic spectrum. After simulation testing, the design of the satisfaction of Smith-Purcell radiation, higher-power THz wave band of the electromagnetic wave output, the actual device provides an effective data.