Cem Yalcin

EECS Department, University of California, Berkeley

Technical Report No. UCB/EECS-2025-18

May 1, 2025

http://www2.eecs.berkeley.edu/Pubs/TechRpts/2025/EECS-2025-18.pdf

In this work, optical, computational, and electronic considerations for high-speed MEMS micromirror-based spatial light modulators (SLMs) are presented with a focus on holographic systems that utilize these elements for point cloud generation. High-speed 3-D holographic patterning of light into point clouds is a prominent technique in a variety of applications ranging from AR/VR displays and holographic projectors to 3-D printing and biology. All-optical neural interfaces utilizing this technique stand to provide a minimally-invasive pathway to circumvent the fundamental limitations of electrical interfaces. However, the refresh rate and temporal capabilities of such holographic systems are heavily bottlenecked by both the computationally intensive computer-generated holography (CGH) algorithms used to compute the hologram and the slow-settling phase-modulating elements in the SLMs used to project the hologram. I first present a computationally light CGH algorithm for point cloud patterning that closely matches the performance of state-of-the-art algorithms at 2-6 orders of magnitude faster computation times. Its non-iterative and memory-light architecture allows for CPUbased computation in ms timescales. Fast computation easily lends itself to time-multiplexingbased approaches for target throughput increase and speckle reduction. Experimental verification confirms the simulation results across SLM formats, target counts, and refresh rates. I then present the analysis, design, and verification of two generations of MEMS mirrorbased SLMs. Firstly, a reduced-degree-of-freedom SLM built from high-speed piston-motion micromirrors is discussed. This device consists of an annular array comprising >23000 micromirrors arranged into 32 concentric rings, and a custom-designed driver ASIC capable of correcting for the global process variations of the MEMS fabrication. The array was used in random-access varifocal operation, demonstrating optical functionality. A secondgeneration family of piston-motion micromirror-based SLMs is presented next, with a pathway to achieving high-degree-of-freedom SLM operation with array sizes of up to 64x64 individually-addressable mirrors. The integration scheme and actuation voltage requirements for these devices necessitated the design of a second-generation ASIC, which is also presented.

Advisors: Rikky Muller

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BibTeX citation:

@phdthesis{Yalcin:EECS-2025-18,
    Author= {Yalcin, Cem},
    Title= {MEMS Mirror-Based High-Speed Spatial Light Modulators},
    School= {EECS Department, University of California, Berkeley},
    Year= {2025},
    Month= {May},
    Url= {http://www2.eecs.berkeley.edu/Pubs/TechRpts/2025/EECS-2025-18.html},
    Number= {UCB/EECS-2025-18},
    Abstract= {In this work, optical, computational, and electronic considerations for high-speed MEMS
micromirror-based spatial light modulators (SLMs) are presented with a focus on holographic
systems that utilize these elements for point cloud generation.
High-speed 3-D holographic patterning of light into point clouds is a prominent technique
in a variety of applications ranging from AR/VR displays and holographic projectors to 3-D
printing and biology. All-optical neural interfaces utilizing this technique stand to provide
a minimally-invasive pathway to circumvent the fundamental limitations of electrical interfaces.
However, the refresh rate and temporal capabilities of such holographic systems are
heavily bottlenecked by both the computationally intensive computer-generated holography
(CGH) algorithms used to compute the hologram and the slow-settling phase-modulating
elements in the SLMs used to project the hologram.
I first present a computationally light CGH algorithm for point cloud patterning that
closely matches the performance of state-of-the-art algorithms at 2-6 orders of magnitude
faster computation times. Its non-iterative and memory-light architecture allows for CPUbased
computation in ms timescales. Fast computation easily lends itself to time-multiplexingbased
approaches for target throughput increase and speckle reduction. Experimental verification
confirms the simulation results across SLM formats, target counts, and refresh rates.
I then present the analysis, design, and verification of two generations of MEMS mirrorbased
SLMs. Firstly, a reduced-degree-of-freedom SLM built from high-speed piston-motion
micromirrors is discussed. This device consists of an annular array comprising >23000 micromirrors
arranged into 32 concentric rings, and a custom-designed driver ASIC capable
of correcting for the global process variations of the MEMS fabrication. The array was
used in random-access varifocal operation, demonstrating optical functionality. A secondgeneration
family of piston-motion micromirror-based SLMs is presented next, with a pathway
to achieving high-degree-of-freedom SLM operation with array sizes of up to 64x64
individually-addressable mirrors. The integration scheme and actuation voltage requirements
for these devices necessitated the design of a second-generation ASIC, which is also
presented.},
}

EndNote citation:

%0 Thesis
%A Yalcin, Cem 
%T MEMS Mirror-Based High-Speed Spatial Light Modulators
%I EECS Department, University of California, Berkeley
%D 2025
%8 May 1
%@ UCB/EECS-2025-18
%U http://www2.eecs.berkeley.edu/Pubs/TechRpts/2025/EECS-2025-18.html
%F Yalcin:EECS-2025-18