Characterisation of MEMs mirrors for use in atmospheric and ocular wavefront correction

Devaney, Nicholas; Coburn, Derek; Coleman, C.M.; Dainty, J. C.; Dalimier, Eugénie; Farrell, Thomas C.; Lara, David; Mackey, David A.; Mackey, Ruth

doi:10.1117/12.773641

Cited by 12 publications

(8 citation statements)

References 9 publications

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“…Thus the modest number of PTT segments (37) in a PTT111 DM provide excellent correction in practice. Experimental results from various groups confirm that the PTT111 DM performs on par with other DMs used for AO retinal imaging systems [1][8]- [10].…”

Section: Iris Ao Mems Segmented Dm Technology Backgroundmentioning

confidence: 66%

Development of high-order segmented MEMS deformable mirrors

Helmbrecht

Kempf

2012

MEMS Adaptive Optics VI

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The areas of biological microscopy, ophthalmic research, and atmospheric turbulence correction require high-order DMs to obtain diffraction-limited images. Iris AO has been developing high-order MEMS DMs to address these requirements. Recent development has resulted in fully functional 489-actuator DMs capable of 9.5 µm stroke. For laser applications, the DMs were modified to make them compatible with high-reflectance dielectric coatings. Experimental results for the 489-actuator DMs with dielectric coatings shows they can be made with superb optical quality λ/93.3 rms (11.4 nm rms) and λ/75.9 rms (20.3 nm rms) for 1064 nm and 1540 nm coatings. Laser testing has demonstrated 300 W/cm 2 power handling with off-the-shelf packaging. Power handling of 2800 W/cm 2 is projected when incorporating packaging optimized for heat transfer.

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Section: Iris Ao Mems Segmented Dm Technology Backgroundmentioning

confidence: 66%

Development of high-order segmented MEMS deformable mirrors

Helmbrecht

Kempf

2012

MEMS Adaptive Optics VI

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“…Of course, when the low-order aberrations dominate the wavefront error, the performance of single Mirao AO is very close to that of dual-DM AO. However, simulation showed that, for a population of 100 eyes using the Thibos model, the static ocular aberrations correction with the Mirao DM (with focus and astigmatism removed) can reach a mean RMS wavefront error of less than 0.03 μ m [14,42,43]. …”

Section: Discussionmentioning

confidence: 99%

Testing of Lagrange multiplier damped least-squares control algorithm for woofer-tweeter adaptive optics

Zou

Burns

2012

Appl. Opt.

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A Lagrange multiplier-based damped least-squares control algorithm for woofer-tweeter (W-T) dual deformable-mirror (DM) adaptive optics (AO) is tested with a breadboard system. We show that the algorithm can complementarily command the two DMs to correct wavefront aberrations within a single optimization process: the woofer DM correcting the high-stroke, low-order aberrations, and the tweeter DM correcting the low-stroke, high-order aberrations. The optimal damping factor for a DM is found to be the median of the eigenvalue spectrum of the influence matrix of that DM. Wavefront control accuracy is maximized with the optimized control parameters. For the breadboard system, the residual wavefront error can be controlled to the precision of 0.03 μm in root mean square. The W-T dual-DM AO has applications in both ophthalmology and astronomy.

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“…The displacement of actuators inside the pupil shows good proportionality to applied voltage while the outer actuator (channel 30) exhibits logarithmic behavior due its slope actuation. Note that, while the inner "curvature" actuators (channels [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] create positive displacements at positive voltage, the "slope" actuators (channels 20-25) induce a slope on the edge of the pupil, creating a negative deflection within the pupil. This characteristic is used in the following section to demonstrate bidirectional actuation.…”

Section: B Actuator Performancementioning

confidence: 99%

“…Electrostatic MEMS DMs can have 100s or 1000s of actuators but have a relatively small stroke (< 5 μm) limited by electrostatic instability [10]. Bimorph DMs, on the other hand, offer large stroke and are much simpler to fabricate than surface-micromachined MEMS DMs, making them appropriate for low-cost applications.…”

Section: Introductionmentioning

confidence: 99%

Single-Crystal PMN-PT MEMS Deformable Mirrors

Park

Horsley

2011

J. Microelectromech. Syst.

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This paper describes microelectromechanicalsystems deformable mirrors (DMs) fabricated from Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 single crystal (PMN-PT) for use in ocular adaptive optics. The DM is a piezoelectric unimorph with 35 actuators on a 13-mm circular membrane. Each actuator inside the 8-mm pupil achieves a static stroke of over 5 μm at 10 V. Dynamic measurements prove that the DM can be operated up to a 2.27-kHz bandwidth. The large stroke with low driving voltage and high operating bandwidth confirm that the DM is a promising candidate for use as a wavefront corrector in vision science applications. The measured piezoelectric properties of the PMN-PT are in close agreement with factory specifications, demonstrating that the piezoelectric properties of single-crystal PMN-PT are not degraded by the bonding and lapping process used here. The large 13-mm-diameter 30-μm-thick membrane is produced by constructing silicon rings to protect the membrane from the considerable compressive stress present in the SiO 2 layer of a silicon-on-insulator wafer. In the prototype mirror, residual stress in the electrode metal results in an initial peak-to-valley surface flatness of 3.3 μm which is reduced to 0.7 μm by iterative computation of the control voltages applied to the electrodes.[ 2011-0145]Index Terms-Adaptive optics (AO), deformable mirror (DM), microelectromechanical systems (MEMS), piezoelectric device, PMN-PT single crystal, unimorph membrane actuator.

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Characterisation of MEMs mirrors for use in atmospheric and ocular wavefront correction

Cited by 12 publications

References 9 publications

Development of high-order segmented MEMS deformable mirrors

Development of high-order segmented MEMS deformable mirrors

Testing of Lagrange multiplier damped least-squares control algorithm for woofer-tweeter adaptive optics

Single-Crystal PMN-PT MEMS Deformable Mirrors

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