Natalie Clark

Design and simulation of advanced surface micromachined micromirror devices for telescope adaptive optics applictions

This paper describes the design, fabrication, modeling, surface characterization, and simulation of advanced surface micromachined micromirror devices that are optimized for adaptive optics applications. Design considerations and fabrication capabilities are presented. Simulation of adaptive optics performance of unique Flexure-Beam and Axial-Rotation Micromirror devices is performed for many common aberrations. These devices are fabricated in the state-of-the-art four-level planarized polysilicon process available at Sandia National Laboratories known as the Sandia Ultra-planar Multi-level planarized MEMS Technology. This enabling process permits the development of micromirror devices with near-ideal characteristics that have previously been unrealizable in standard three-layer polysilicon processes. This paper describes such characteristics as elevated address electrodes, array wiring techniques, planarized mirror surfaces using chemical mechanical polishing, unique post-process metallization, and the best active surface area to date.

Intelligent vision systems using dynamic neural networks

The design of a silicon eye using dynamical neural networks. Our silicon eye is capable of not only able to compensate for defocus, but it can also compensate for other aberrations including astigmatism, coma, and spherical aberrations. In addition, the silicon retina acts as a reconfigurable dynamic neural network to enable real-time image processing. The silicon eye uses three key enabling technologies. First, high-speed active pixel photo-diodes are used as photo-detectors for both imaging and for wavefront sensing. The design of the active pixel photo- detectors is described along with experimental results characterizing their performance. Second, the analog signals received from the photo-detectors and processed by the active pixel circuitry is fed into a smart vision chip. The smart vision chip is a reconfigurable neural network capable of real-time reconstruction of the phase information associated with the imaging system. The micro mirrors are active optic devices that can be used to compensate for optical aberrations. Experimental results obtained from the circuit implementation of the dynamical network networks are presented. The experimental results obtained from our intelligent vision system demonstrate that dynamical neural networks offer advantages in speed, cost, size, and power consumption.

Design and performance evaluation of a silicon eye using micro-mirrors

Develops a new paradigm, based on massively parallel analog processing coupled with a MEMs micro-mirror device; for developing intelligent vision systems that is capable of performing adaptive optics at rates exceeding 1 kHz and 3D imaging at bandwidths exceeding 100 Hz. The design and modeling methodologies associated with our smart vision chip are presented along with experimental results that characterize its performance. We also present design and modeling methodologies of micro-mirror devices along with experimental results that characterize their performance in typical adaptive optic systems. Finally, we present modeling and simulation methodologies of adaptive optics systems along with experimental results used to design and test an adaptive optic system. The design and modeling methodologies that are presented lend themselves to facilitating the design and development of a wide variety of other sophisticated vision systems. In addition to speed, the approach offers advantages in low cost batch fabrication, compact size, low power consumption, and radiation tolerance, making it ideal for many applications.

Silicon adaptive optic systems using micromirrors

Many factors contribute to the aberrations induced in an optical system. Atmospheric turbulence between the object and the imaging system, physical or thermal perturbations in optical elements degraded the systems point spread function, and misaligned optics are the primary sources of aberrations that affect image quality. The design of a non- conventional real-time adaptive optic system using a micro- mirror device for wavefront correction is presented. The adaptive optic system uses a VLSI circuit that can be reconfigured for use with many wavefront sensor including the Hartmann, shearing, and curvature wavefront sensors. The unconventional adaptive optic imaging systems presented offer advantages in speed, cost, power consumption, and weight. Experimental and modeling results that characterizes the performance of each wavefront sensor in the micro-mirror adaptive optic system are presented.

Intelligent Star Tracker

Describes the Intelligent Star Tracker System. The Intelligent Star Tracker System incorporates an adaptive optic catadioptric telescope in a silicon carbide housing. Leveraging off of the active optic technologies, the novel active pixel position sensors (APPS) enable wide dynamic range and allow simultaneous imagery of faint and bright stars in a single image. Moreover, the APPS, in conjunction with the adaptive optics technologies, offer unprecedented accuracy in altitude and navigation applications.

Design and performance evaluation of a silicon eye using micromirrors

We have developed a new paradigm, based on massively parallel analog processing coupled with a MEMS micromirror device, for developing intelligent vision systems that is capable of performing adaptive optics at rates exceeding 1 kHz and 3D imaging at bandwidths exceeding 100 Hz. The design and modeling methodologies associated with our smart vision chip are presented along with experimental results that characterize its performance. We also present design and modeling methodologies of our micromirror devices along with experimental result that characterize their performance in typical adaptive optic systems. Finally, we present modeling and simulation methodologies of adaptive optics systems along with experimental results used to design and test an adaptive optic system. The design and modeling methodologies that are presented lend themselves to facilitating the design and development of a wide variety other sophisticated vision systems. In addition to speed, our approach offers advantages in low cost batch fabrication, compact size, low power consumption, and radiation tolerance, making it ideal for many applications.