Propagation properties of non-paraxial Lorentz beam

Based on the theory of the second intensity moment, the results of the far-field divergence angle, near-field divergence angle, waist width and beam propagation factor of non-paraxial Lorentz beam are derived, and the relationship of them versus the corresponding waist width and the wavelength is studied. The result indicates that, compared with the non-paraxial Gaussian beam, under the condition of satisfying physical mechanism of diode laser, the non-paraxial Lorentz beam is more appropriate with the actual situations of diode laser beam. Accordingly, the non-paraxial Lorentz beam is a more appropriate model to describe laser sources with small size and high divergence such as diode laser.