Characterization of Anisotropic Leaky Mode Modulators for Holovideo

Abstract

Holovideo displays are based on light-bending spatial light modulators. One such spatial light modulator is the anisotropic leaky mode modulator. This modulator is particularly well suited for holographic video experimentation as it is relatively simple and inexpensive to fabricate. Some additional advantages of leaky mode devices include: large aggregate bandwidth, polarization separation of signal light from noise, large angular deflection and frequency control of color. In order to realize these advantages, it is necessary to be able to adequately characterize these devices as their operation is strongly dependent on waveguide and transducer parameters. To characterize the modulators, the authors use a commercial prism coupler as well as a custom characterization apparatus to identify guided modes, calculate waveguide thickness and finally to map the device's frequency input and angular output of leaky mode modulators. This work gives a detailed description of the measurement and characterization of leaky mode modulators suitable for full-color holographic video.

Status of Leaky Mode Holography

“…An example of a typical leaky mode optical path is shown in Figure 2a below. In this particular arrangement, the light of TE polarization enters a proton exchanged waveguide via input grating (or via evanescent prism coupling [6,7]). The guided light encounters a counter-propagating surface acoustic wave (SAW), generated by an interdigital transducer (IDT) [8], that couples the guided light from a discrete TE guided mode to a spectrum of TM-polarized leaky modes.…”

Progress on characterization and optimization of leaky-mode modulators for holographic video

“…Additionally, leaky-mode modulators are readily fabricated using straightforward wafer-based photolithographic processes, which makes it possible to fabricate them inexpensively. 9 Leaky-mode modulators have the additional advantages of polarization rotation of signal light, increased angle of deflection, and frequency control of color. Much of the work done since these modulators were first introduced has focused on optimizing frequency control of color.…”