It has long been recognized in the design of micromirror-based optical systems that balancing static flatness of the mirror surface through structural design with the system’s mechanical dynamic response is challenging. Although a variety of mass reduction approaches have been presented in the literature to address this performance trade, there has been little quantifiable comparison reported. In this work, different mass reduction approaches, some unique to the work, are quantifiably compared with solid plate thinning in both curvature and mass using commercial finite element simulation of a specific square silicon-on-insulator–based micromirror geometry. Other important considerations for micromirror surfaces, including surface profile and smoothness, are also discussed. Fabrication of one of these geometries, a two-dimensional tessellated square pattern, was performed in the presence of a 400-μm-tall central post structure using a simple single mask process. Limited experimental curvature measurements of fabricated samples are shown to correspond well with properly characterized simulation results and indicate ∼67% improvement in radius of curvature in comparison to a solid plate design of equivalent mass.
Our investigation addresses the modeling, design and fabrication of artificial structures, commonly called metamaterials.
Metamaterials enable electromagnetic properties which do not naturally exist from basic structural symmetry. This
investigation focuses on the modeling, fabrication and testing of metamaterials at terahertz wavelengths. This research
utilizes a foundry fabrication process called PolyMUMPs to construct the metamaterial array. The PolyMUMPS process
is commonly used for MEMS devices and consists of three polysilicon and two silicon dioxide layers. An array of split
ring resonators consisting of the polysilicon and silicon dioxide layers was constructed. The split ring resonators are an
important aspect to the metamaterial because they allow us to take advantage of structural properties such as scaling,
resonant frequency response, and magnetic flux. The metamaterial structure obtains its symmetry from the etching
process used to isolate the individual patterns. The "as-built" figure of merit (FOM) is defined as the ratio of the real
component to the imaginary component of the refractive index. By comparing the analytical and FEM models to identify
key limitations of the FOM structures, this investigation will point out manufacturing limitations that can be adjusted to
improve the FOM. By gaining a higher ratio to the FOM, this improves the overall performance of the metamaterial
structure at the selected wavelength. Through the understanding obtained from the modeling data and actual
manufacturing comparison, changes to key parameters which limit the FOM can lead to metamaterial array
improvements and ultimately to better components suitable for terahertz applications.
This paper discusses our investigation into artificial structures called metamaterials. Metamaterials make it
possible to achieve electromagnetic properties not existing in nature. The investigation focuses on the modeling,
fabrication and testing of metamaterials at optical frequencies. The main purpose of this research is to identify a method
to fabricate the artificial structures. We identify limitations in the fabrication process which are used to build the
metamaterials. Measured reflectance data from fabricated devices is then compared with modeled data to identify
limitations affecting the "as-built" figure of merit (FOM). Understanding the parameters which limit the FOM will lead
to device fabrication improvements and ultimately to components suitable for optical applications such as optical
surveillance systems.
This paper will investigate a novel thermally actuated micro-shutter design for micro-optical-electro-mechanical system
(MOEMS) applications. The use of actuators in optical systems has improved with new developments in micro-electromechanical
systems (MEMS) designs for use as components in optical systems. Thermal actuators provide a novel
approach to scaling MOEMS to reduce size, weight and power of optical systems. Through the investigation of an
aluminum electro-thermal actuator, we developed an in-house fabrication method which operates at less than one volt to
aid in reducing the size, weight, and power of the optical system. This paper discusses several challenges and
opportunities that may arise from the fabrication of thermally actuated micro-shutter designs which can help improve the
actuator's uniformity, reproducibility, and reliability. In addition, we discuss the characterization of the thermal actuator
micro-shutter to include mechanical, electrical and optical properties. The "switching" speed of the thermal actuator will
also be assessed from a scaling perspective to determine usability.
This paper will investigate micro-shutter MEMS "fabrication techniques" and processes to identify opportunities and
barriers for successful implementation of micro-shutter technologies to enable adaptive coded aperture imaging and nonimaging
systems. The use of photonic MEMS for creating adaptive coded apertures has been gaining momentum since
2007. Both Industry-based1, 2 and University-based3 studies have demonstrated their unique solutions for implementing
MEMS-based micro-shutter technologies; however, there are many unique and novel MEMS-based "fabrication and
characterization" processes and solutions that will be considered herein as we explore micro-shutter technologies. This
paper discusses challenges and opportunities that may arise from in-house fabrication of MEMS which may prevent
and/or improve structural uniformity, reproducibility, & reliability. This paper will also discuss characterization of the
micro-shutters to include mechanical, electrical and optical properties. The "open and close" speeds of the micro-shutter
device will also be assessed from a scaling perspective to determine usability.
This paper will investigate micro-shutter developments for IR applications. By demonstrating a interrupter mechanism
MEMS design, we will show how to implement a micro-shutter technology to enable adaptive coded aperture imaging
and non-imaging systems. The use of Photonic MEMS for creating adaptive coded apertures, for surveillance systems,
has been gaining momentum since 2007 1,2. Through the investigation of the interrupter mechanism 3,4, we will
demonstrate a novel approach for IR applications. This paper discusses challenges and opportunities that may arise from
the fabrication of a MEMS interrupter mechanism. We discuss the characterization of the micro-shutter to include
mechanical, electrical and IR properties. The "open and close" speeds of the micro-shutter device will also be assessed
from a scaling perspective to determine usability through modeling and simulation.
This paper will investigate a novel agile-pitch diffraction grating array design and phenomenology, for micro-shutter
Photonic MEMS technologies, to enable adaptive coded aperture imaging and non-imaging systems. The use of Photonic
MEMS for creating adaptive coded apertures, for surveillance systems, has been gaining momentum since 2007 1,2. The
use of the agile-pitch diffraction grating has also been used previously to perform beam-dispersion which is a critical
step in imaging processing 3. Through the investigation of new diffraction grating approaches, we hope to show a
reconfigurable capability for agile beam steering for adaptive coded apertures surveillance imaging and non-imaging
systems. This paper discusses challenges and opportunities that may arise from in-house fabrication of agile-pitch
diffraction grating array micro-shutter designs which may prevent and/or improve structural uniformity, reproducibility,
& reliability. This paper will also discuss characterization of the micro-shutters to include mechanical, electrical and
optical properties. The "open and shut" speeds of the micro-shutter device will also be assessed from a scaling
perspective to determine usability.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.