Recording of the multiplexed Bragg diffraction gratings using the phase mask for the near-eye display

With the development of augmented reality displays and integrated photonics devices, researchers are faced with the task of developing new methods for recording the waveguide holograms and creating the diffractive waveguides. Recording of such type diffraction elements is associated with increasing the complexity level since large convergence angles of the recording beams must be provided. The object wave must be inside the substrate during recording. A manuscript demonstrates a stable and simple method for multiplexed recording of the Bragg diffraction gratings for AR displays using phase masks. This recording technique is accompanied with no need in strong vibration isolation because of interferometric branches absence in the optical scheme. Presented research is distinguished by conical illumination of the phase mask with a single recording laser beam to manufacture the slant volume gratings for AR waveguide displays. An important result for the research is in experimental confirmation of the beneficial application of non-selective surface phase mask in comparison with volume selective one. Diffraction waveguides in this experiment made of photo-thermo-refractive (PTR) glass — unique material for integration of phase diffraction elements into waveguide platform. Creation of substrate-mode multiplexed Bragg gratings in planar waveguide made from PTR glass is the challenge of the research.