Characterization and closed-loop performance of a liquid mirror adaptive optical system

A deformable mirror based on the principle of total internal reflection of light from an electrostatically deformed liquid–air interface was realized and used to perform closed-loop adaptive optical (AO) correction on a collimated laser beam aberrated by a rotating phase disk. Equations describing the resonant and oscillatory behavior of the...

Characterization and closed-loop AO performance of a liquid deformable mirror

Closed-loop adaptive optical correction using a deformable mirror based on the total internal reflection (TIR) from an electrostatically deformed liquid-air interface was performed on a collimated beam of a HeNe-laser that was aberrated by a rotating phase disk. The frequency response of the system was measured and the influence of liquid...

Integrated adaptive optics system for small telescopes

We describe a compact integrated module implementing a low-cost adaptive optics system. It is targeted as a correction system for small telescopes with primary mirror diameter up to 1 m, operating on a natural guide star with magnitude at least 4 (for a 25 cm telescope). It is supposed to provide stable diffraction-limited imaging of stars,...

IC-compatible microspectrometer using a planar imaging diffraction grating.

The design and performance of a highly miniaturized spectrometer fabricated using MEMS technologies are reported in this paper. Operation is based on an imaging diffraction grating. Minimizing fabrication complexity and assembly of the micromachined optical and electronic parts of the microspectrometer implies a planar design. It consists of two...

Fabrication of an imaging diffraction grating for use in a MEMS-based optical microspectrograph

Optimal implementation of a microspectrometer based on a single flat diffraction grating

An analytical model has been developed and applied to explore the limits in the design of a highly miniaturized planar optical microspectrometer based on an imaging diffraction grating. This design tool has been validated as providing the smallest possible dimensions while maintaining acceptable spectral resolution. The resulting planar...

Coupling of a CMOS Optical Sensor to a Micromachined Deformable Mirror with an Adaline Neural Method

We report on the preliminary results of an Adaline neural method for the coupling of a custom CMOS wavefront sensor to a micromachined adaptive mirror. The algorithm does not rely on a fixed basis matrix -as opposed to traditional methods-, offers excellent immunity to round-off errors and admits real-time input adaptability to speed up...

Piezoelectric deformable mirror with adaptive multiplexing control

Multiplexing control of a multichannel piezoelectric deformable mirror

Addressing of massive arrays of piezoelectric actuators is usually achieved by using separate high-voltage output drivers, one per channel. This approach applied to high-order adaptive optics systems results in complex, expensive and vulnerable to handling abuse driver electronics, hardly scalable to 103-104 actuators. To reduce the number of...

Estimation of the total error of modal wavefront reconstruction with Zernike polynomials and Hartmann-Shack test

The paper discusses the influence of the Hartmann-(Shack) wavefront sensor geometry on the total error of modal wavefront reconstruction. A mathematical model is proposed which describes modal wavefront reconstruction based on Hartmann or Hartmann-Shack sensor in terms of linear operators. The modal covers the most general case and is not...

CMOS integrator based lock-in pixel for heterodyne interferometry

This article presents a prototype of a CMOS phase sensor for high accuracy (1 Angstrom) heterodyne interferometry. Switched integrators realization of a lock-in pixel for 4-bucket phase detection algorithm is described and illustrated by experimental results. Factors that limit the accuracy of this implementation and possible ways for its...

Liquid crystal wavefront corrector on silicon

A reflective-type liquid crystal (LC) wavefront corrector with modal addressing is described. The corrector’s backplane has an array of pixel electrodes interconnected by a network of discrete resistors. The resistive network serves to form the local voltage profile that controls the phase distribution generated in the liquid crystal layer. This...

Subjective adaptive correction of the aberrations of the human eye

We designed and built an experimental setup for subjective (manually controlled) correction of up to 12 orthogonal terms (excluding tilts and defocus) of the aberration of the human eye. In our experiments, the subject was looking through an adaptive optical system at the USAF resolution chart. By using the arrow keys of the computer keyboard,...

Phase extraction from three interferograms with different unknown tilts

We propose an algorithm for phase retrieval from three interferograms which differ only by an arbitrary unknown tilt terms in the phase. The method is illustrated by examples.

Modal wavefront correction with liquid crystals: Different options

Liquid crystal (LC) wavefront correctors with modal addressing are described. Three different approaches are considered. The first one is based on a continuous thin-film resistive layer. This layer is used for forming of the local voltage profile that controls the phase distribution across the corrector’s aperture. The second approach is a...

Using 50-mm electrostatic membrane deformable mirror in astronomical adaptive optics

Membrane micro-machined deformable mirrors (MMDM) feature low cost, low power consumption, small size and absence of hysteresis. Interested in using such a device for the adaptive optics system at the SOAR 4.1-m telescope, we evaluated the performance of a 79-channel 50-mm (pupil size 35mm) MMDM from OKO Technologies. The measured influence...

Silicon micro-optics for smart light control

We present an overview of the results of our recent research in the field of adaptive optical components based on silicon microtechnologies, including membrane deformable mirrors, spatial light modulators, liquid-crystal correctors, wavefront sensors, and both spherical and aspherical micro-optical components. We aim at the realization of...

Technology and applications of micromachined silicon adaptive mirrors

The technology of low-cost high-quality micromachined adaptive mirrors is reported. Adaptive mirrors are fabricated by combining bulk silicon micromachining with standard electronics technologies. Mirrors with tens of control channels, having RMS initial deviation from plane of the order of ?/20 and a range of surface deflection of 10 to 20 ?m...