Propagation properties of cosine-Gaussian beams in gradient-index medium

Using the method of generalized Huygens-Fresnel diffraction integral, this paper deduces the analytical expression of cosine-Gaussian beams propagating in a gradient-index medium, and analyzes the corresponding propagation properties of cosine-Gaussian beams. The influence of the medium’s gradient-index parameter and the modulation parameter on the propagation properties is also discussed. The results show that the intensity of cosine-Gaussian beams propagating in a gradient-index medium varies periodically on axis. The transverse intensity distribution is largely influenced by the modulation parameter. The transmission of cosine-Gaussian beams is unstable, but the cosine-Gaussian beams can be reshaped through appropriately adjusting the modulation parameter at some spatial position.