Annular Beam Pumped Highly Efficient LG_0,1Vortex Yb:YAG Microchip Laser

Using annular beam as pump source to generate vortex beam has natural advantages.The microchip laser which is using the focused annular beam directly acting on the solid laser medium can simplify the experimental process and generate the vortex beam conveniently and efficiently.More and more researchers pay attention to the simple and effective generation of vortex beams with different topological charges,but ignore the theoretical research of annular beam pumping.Because of the limitation of the phase factor of the focusing lens,the field distribution of the focal position and the transmitted at the non-focus cannot be unified in one analytic expression solved by the diffraction integral formula,solve the field distribution of focus annular beam by two fast Fourier transforms is also difficult.So,it is necessary to find an analytic expression that can reasonably describe the circular beam focusing transmission,which requires exploring the focusing characteristics of the annular beam.This thesis explored the characteristics of the annular beam,the circular beam is described by the equation of the circle in the ideal cylindrical coordinate system,according to the circular beam focusing transmission algorithm,the field distribution of the focal position and near the focus point are obtained,the axial beam intensity distribution near the focus position and focal plane beam intensity distribution are also explored in the influence of duty ratio.Then,using the focusing characteristics of the annular beam an analytical expression that can reasonably describe the internal beam intensity distribution of the laser crystal by using the focus annular beam pump is found,and then coupled with the vortex laser of different LG modes to detect the matching degree.Provides a theoretical basis for vortex beam generated by focus annular beam pump.On the basis of this theory,a high beam quality,highly efficient radial polarization Yb:YAG microchip laser was designed to provide a laser source for related applications.