Content of research

Optical information processing, transmission, recording and reproduction are performed using the intensity, polarization and spatially uniform phase of laser light. The transmission capacity can be increased through multiplexing using different frequencies. In contrast, the spatial characteristics of light form an unexplored area that has not been actively utilized until now. Based on this background, information multiplexing using Laguerre-Gaussian (LG) light and quantum information processing using the orbital angular momentum (topological charge) that characterizes LG light have been attracting attention as a step to overcome the limitation of information processing capacity. In this study, we have utilized material interaction and realized the mode control of LG light and the conversion and conservation of orbital angular momentum using short-pulsed light, as well as space-division multiplexing fiber transmission.

Potential for social implementation

• ・Increasing the capacity of optical recording
• ・Space-division multiplexing
• ・Multidimensional information processing by mode conversion
• ・Evaluation of spatial coherence
• ・Spatial mode control of semiconductor lasers

Appealing points to industry and local governments

Light with characteristic spatial properties, such as Laguerre-Gaussian light, is innovative in that it uses optical parameters that have not been used in the past. Meanwhile, there is a need for innovative wavefront control, transmission technology and light source development to maintain the spatial characteristics. Although our efforts concern only one part of this field, we hope that our presentation will be of interest to a wide audience.