Static Structures in Leaky Mode Waveguides

Abstract

Featured Application: The overarching contextual objective of this research is to create transparent, near-eye devices for holographic video display. Abstract:In this work, we suggest a new method of expanding the field of view in bottom-exit, leaky mode devices for transparent, monolithic, holographic, near-eye display. In this approach, we propose the use of static, laser-induced, grating structures within the device substrate to break the leaky mode light into diffracted orders. We then propose to use carefully timed illumination pulses to select which diffracted order is visible to the eye at every display refresh interval (up to 100 kHz). Each of these orders becomes a view for a different image point. To describe this new method, we use K-vector analysis. We give the relevant equations and a list of parameters which lead to a near-eye geometry with little or no overlap in higher-order view zones. We conclude that it should be possible to increase the field of view of our bottom-exit, leaky mode devices by as much as one order of magnitude by simply adding a laser-induced grating structure to the substrate and by carefully timing the device illumination. If successful, this method would make possible a transparent, holographic, near-eye display that is simple to fabricate, relative to pixelated approaches, and which has a wide field-of-view relative to our current bottom-exit displays.

Status of Leaky Mode Holography

“…This reduction is shown graphically using k-surfaces in Figure 10b. Proposed approaches to ameliorate this reduction include wavelength-coded boresight multiplexing [50], the use of light field expansion optics [51], and the use of induced diffractive structures [52]. Proposed example of monolithic near-eye display (bottom).…”

“…Jolly et al and Smalley et al proposed methods to overcome this reduction by the use of femtosecond laser-induced reflective and diffractive structures, respectively. In the diffraction case, induced gratings form a Dammann grating to split the leaky mode outputs into several diffractive orders (see Figures 11 and 12c) [52,53]. If the position of the user's eye is known, and the illumination can be strobed, then it has been shown in simulation that these orders can be stitched together (Figure 12a,b) to form a large total field of view of approximately 51 deg (Figure 11a,b), or view-angle depending on whether the user is fixed or moving.…”

“…If the position of the user's eye is known, and the illumination can be strobed, then it has been shown in simulation that these orders can be stitched together (Figure 12a,b) to form a large total field of view of approximately 51 deg (Figure 11a,b), or view-angle depending on whether the user is fixed or moving. Reprinted with permission from [52].…”

“…(b) viewzones for a multiorder output. (c) Diffracted orders from a laser-induced grating in the bulk of lithium niobate.Reprinted with permission from[52].…”

Editorial on Special Issue “Holography, 3-D Imaging and 3-D Display”

“…There are seven papers under the category of 3-D display. Pettingill et al investigate static structures in leaky mode waveguides for transparent, monolithic, holographic, near-eye display [20]. Kim et al provide their initial results on an electronic tabletop holographic display and hope the work will give guidance for the future development of commercially acceptable holographic display systems [21].…”