Array formation of optical vortices using in-line phase modulation

In this paper, we demonstrate the formation of optical vortices (OV) array through in-line modulation of phase distributions using the approach of concatenation. This approach is non-interferometric and provides flexibility in the selection of the parameters that characterize the OVs and its array. Utilizing this feature, an array of high order OVs even with non-zero radial indices can be generated. An array of fractional order OVs can also be realized. Experimental and simulation results have been presented that verifies the feasibility.