Design of high-speed phase-only spatial light modulators with two-dimensional tunable microcavity arrays

Abstract

Spatial light modulators (SLMs) are central to numerous applications ranging from high-speed displays to adaptive optics, structured illumination microscopy, and holography. After decades of advances, SLM arrays based on liquid crystals can now reach large pixel counts exceeding 10 6 with phase-only modulation with a pixel pitch of less than 10 µm and reflectance around 75%. However, the rather slow modulation speed in such SLMs (below hundreds of Hz) presents limitations for many applications. Here we propose an SLM architecture that can achieve high pixel count with high-resolution phase-only modulation at high speed in excess of GHz. The architecture consists of a tunable two-dimensional array of vertically oriented, one-sided microcavities that are tuned through an electro-optic material such as barium titanate (BTO). We calculate that the optimized microcavity design achieves a π phase shift under an applied bias voltage below 10 V, while maintaining nearly constant reflection amplitude. As two model applications, we consider high-speed 2D beam steering as well as beam forming. The outlined design methodology could also benefit future design of spatial light modulators with other specifications (for example amplitude modulators). This high-speed SLM architecture promises a wide range of new applications ranging from fully tunable metasurfaces to optical computing accelerators, high-speed interconnects, true 2D phased array beam steering, and quantum computing with cold atom arrays. arXiv:1908.06495v1 [physics.optics]

Electro-optic spatial light modulator from an engineered organic layer

“…Current demonstrations of monolithic metasurfaces from χ (2) materials typically trade off an operation around a sharp resonance in materials with moderate but broadband χ (2) effect e.g., in lithium niobate 18,19 or colloidal nonlinear nanocubes 20 against an efficient χ (2) effect in application-specific engineered III-V heterostructures, which is however narrowband and located around its bandgap 6 . While many demonstrations are single-pixel, few exciting multifunctional metasurfaces with multiple electronic controls have emerged experimentally 6,21,22 and theoretically 23 . Important to mention are also metasurfaces based on transparent conductive oxides 22,[24][25][26] that have enabled SLMs recently 27 , gate-tunable low-dimensional materials 28 or phase change materials such as e.g., GST [29][30][31][32][33] that are excellent candidates in scenarios, where high switching speeds are not required.…”

Artificial Intelligence Accelerators Based on Graphene Optoelectronic Devices

“…[ 42 ] In addition, we only presented one possible example of SLM design and many other designs of high‐performance SLMs can be also utilized and adapted in our architecture. [ 43–45 ]…”

Active Modulating the Intensity of Bifocal Metalens with Electrically Tunable Barium Titanate (BTO) Nanofins

“…The shift of the refractive index is proportional to applied electric field because of the electro-optic effect named Pockels effect. Meanwhile, BTO is chemically and thermally stable and has ultrafast modulation speed (sub-ps) [ 29 , 30 ]. Additionally, compared with other electric-optical materials such as LiNbO 3 [ 31 ], the Pockels coefficient of BTO is much larger.…”