Beam Duplicator Consisting of a Waveguide Coupler and Display on a Head Mounted Display

Abstract

We fabricated a SiO₂ embedded-TiO₂ slanted nanograting sample using reactive ion etching and electron beam lithography techniques and investigated their optical responses. Surface morphology for the fabricated gratings was monitored by a scanning electron microscope (SEM). According to the SEM observation, the cross-section shape of gratings was like saw-tooth with a slanted angle of 55°, and their periodicity was determined to be ∼704 nm. In the measurement, high order diffraction with intensity of 4.63% at 0th and 14.8% at +1st at the interface between SiO₂ and TiO₂ were obtained by irradiating a transverse electric polarized beam with wavelength 532 nm at the incident angle 17.5° from the rear side of TiO₂. The 0th order diffraction beam was passed through the SiO₂ substrate sample and, then, directly emitted into the atmosphere. The emitted beam can create a virtual reality (VR) image to project on a board. On the other hand, the +1st order diffraction beam is guided by a zigzag into the SiO₂ substrate. During waveguide, the beam duplicated using optical property either a forbidden system or an accepted system permits partial penetration to a permeable display mounted on a surface of the SiO₂ substrate. Penetrated duplication beams are waveguided with total internal reflection in a display, resulting in emission from the side face of the permeable display. The emitted beam can provide the duplicated VR images in the atmosphere. In future, this integrated devise will play an important role for a head mounted display creating a projection VR and duplicated VR simultaneously.