SD&A 2020: Monolithic surface-emitting electroholographic optical modulator
Channel: IS&T Electronic Imaging (EI) Symposium
Date: 2020-07-22

This presentation was delivered at the 31st annual Stereoscopic Displays and Applications conference (27-29 January 2020) held in Burlingame, CA USA. For more information see: http://stereoscopic.org 

Title: Monolithic surface-emitting electroholographic optical modulator (SD&A 403)

Speaker: Gregg E. Favalora, The Charles Stark Draper Laboratory, Inc. (USA)

Abstract: Electronic holography is an avenue for high-quality autostereoscopic display, as holography is capable of reconstructing 3-D scenes with the utmost of realism. Towards the goal of practical electroholographic display, researchers in the field continue to develop or improve a suite of enabling components and processes. A particularly critical avenue of development is in optical modulator technology. Optical modulators for electroholography include pixelated spatial light modulators, bulk acousto-optical modulators (AOMs), and of recent interest to the community, surface acoustic wave (SAW) AOMs such as edge-emitting and hypothesized surface-emitting SAW AOMs. We report the first demonstration, to our knowledge, of a surface-emitting SAW AOM. A monolithic device was created from a lithium niobate substrate having buried optical waveguides, interdigital electrodes (IDTs), and a subwavelength backside grating. The device carries induced holographic fringes (the SAWs) in response to analog electronic waveforms applied to an IDT. Waveguided input illumination at 640 nm is injected by prism coupling and holographically diffracted within the substrate upon interaction with the SAW. After encountering the backside surface grating, the modulated light exits the front surface of the modulator and is measured by a detector on a rotary stage. As a fundamentally analog and continuous-space device, the waveforms, and hence the holographic fringes, can carry a variety of formats. We demonstrate the modulator's behavior as an 8 mm linear electrohologram and characterized the device's response to waveforms including a 9-region pattern of hogels.

Biography: Gregg Favalora is a specialist in autostereoscopic displays. He is the Group Leader of Sensors and Imaging Systems at Draper, in Cambridge, Massachusetts. Earlier in his career, Gregg was co-founder of Actuality Systems, developers of a variety of display systems, including the Perspecta volumetric display.

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