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The scintillation index of vortex beam in simulated atmospheric turbulence is experimentally investigated. The fluctuation of the intensity can be effectively reduced by vortex beams. In particular, the reduction of scintillation is more pronounced for vortex beams with larger topological charge.Propagation of laser beams through turbulent atmosphere has attracted much attention because of their applications in many areas including free space optical communications, remote sensing, imaging systems, and laser radar. The intensity, degree of coherence, degree of polarization, beam spreading of the laser beams will be affected by the turbulence [1-3]. Among them, scintillation (i.e., the fluctuation of intensity) manifesting itself as signal dependent noise is one of the most important factors as the scintillation degrades the signal-to-noise ratio and may increase the bit error rate. The properties (beam shape, phase, polarization, coherence) of the incident beams strongly affect the scintillation. Therefore, it is of great importance to find a special light beam whose scintillation is less affected by turbulence. It has been indicated that the on-axis scintillation of an elliptical Gaussian beam and a dark hollow beam is smaller than that of a circular Gaussian beam in a weakly turbulent atmosphere under certain conditions [4,5]. The degradation of the degree of the source coherence may cause a significant reduction of scintillation index which means that the partially coherent beams are less affected by the turbulence than coherent beams [6]. An appropriately chosen nonuniformly polarized coherent beam is also demonstrated to have smaller scintillation than beams of uniform polarization [7]. Another solution for scintillation reduction is replacing the single incident beam by beam arrays. The scintillation of a beam array can be effectively reduced by adjusting the spatial separation of the beams [8].Beams with spiral phase are regarded as vortex beams, in which each photon carries orbital angular momentum (OAM) [9]. The OAM can be used to encode data onto a laser beam for transmitting information in free-space optical systems [10,11]. Such an application provides a possibility to increase the information density together with an inherent security enhancement [10]. The influence of the turbulent atmosphere on the OAM of the vortex beams has been investigated, and the results demonstrated that the OAM of the beam can be well preserved in a long propagation distance in weak turbulence [12]. The scintillation of vortex beams in turbulence has also been studied [13,14]. However, most of the studies have been limited to theoretical simulations [13]. Moreover, only vortex beams with topological charge n = 1 are considered in these papers [13,14]. In this study, we will focus on the scintillation of vortex beams in turbulence. The atmospheric turbulence is simulated by rotating a random phase plate. Both vortex beams with topological charge n = 1 and larger topological charge are investigated.Assume that the electric fi...