Encoding and Multiplexing of 2D Images with Orbital Angular Momentum Beams and the Use for Multiview Color Displays

Abstract

<jats:p>The orthogonal nature of different orbital angular momentum modes enables information transmission in optical communications with increased bandwidth through mode division multiplexing. So far the related works have been focused on using orbital angular momentum modes to<jats:italic> encode/decode and multiplex point-based on-axis signals</jats:italic> for maximum data channel numbers and capacity. Whether orbital angular momentum modes can be utilized to encode/decode<jats:italic> off-axis signals</jats:italic> for multiplexing in two-dimensional space is of significant importance both fundamentally and practically for its enormous potential in increasing the channel information capacity. In this work, a direct use of orbital angular momentum modes to<jats:italic> encode/decode and multiplex two-dimensional images</jats:italic> is realized in a scalable multiview display architecture, which can be utilized for viewing three-dimensional images from different angles. The effect of off-axis encoding/decoding and the resultant crosstalk between multiplexed different two-dimensional views are studied. Based on which, a color display of good image quality with four independent views is demonstrated. The resolution of the decoded images is analyzed and the limitation of this approach discussed. Moreover, a spatially multiplexed data communication scheme is also proposed with such a two-dimensional encoding/decoding approach to significantly enhance the data transmission capacity in free space for future data communication needs.</jats:p>

Angle Multiplexing Optical Image Encryption in the Fresnel Transform Domain Using Phase-Only Computer-Generated Hologram

“…The contributions of optical experiments on image multiplexing based on various manipulation schemes have been widely proposed since last decade [36][37][38][39][40][41]. For example, the multiplexing methods for images and movies can be based on aperture-modulated optical systems [36], joint transform correlator architectures [37,38], using the CGH and maximum length cellular automata [39], the DRPE and orthogonal phase encoding [40], and the multiplexed view-coded orbital angular momentum beam [41]. The practical issues associated with the optical experiments of the proposed method can be explored in these studies.…”

Effect of azimuthal phase gradient variation on optical spiral vortex

“…These beams exhibit a unique annular intensity distribution with phase singularities at the center, resulting in zero intensity. Thanks to its distinct spiral phase distribution and the ease of experimental implementation, OV have found extensive applications in various areas such as optical manipulation [2][3][4] , free-space optical communication [5][6][7] , quantum communication [8][9][10] , and high-security encryption [11][12][13] . Moreover, the complete orthogonality between OV with different topological charges enables the multiplexing of OAM channels, providing unlimited transmission capacity for optical communication 7,14,15 .…”

Optical spiral vortex from azimuthally increasing/decreasing exponential phase gradients

“…Light carrying OAM has a helical phase structure that can be described using e iLφ , where φ is the azimuth angle, and L denotes the topological charge. The optical vortex beam (OV), with its unique spiral phase wavefront structure and zero light intensity distribution at its center [2] , holds great potential for applications in optical manipulation [3][4][5] , free-space optical communications [6][7][8] , quantum communications [9][10][11] , high-security encryption [12][13][14] , among other fields. Multiplexing of OAM channels can add unlimited transmission capacity to optical communications [8,15,16] .…”