os, 9/16/99 MICROMACHINING AND MICROFABRICATION TECHNOLOGY FOR ADAPTIVE OPTICS Olav Solgaard Acknowledgements: P.M. Hagelin, K. Cornett, K. Li, U. Krishnamoorthy, D.R. Pedersen, M. H. Guddal, E.J. Carr, V. Laible, BSAC: R.S. Muller, K. Lau, R. Conant, M. Hart Research Funding: NSF, BSAC, SMART

os, 9/16/99  MIRRORS Texas Instrument’s DMD NASA's Next Generation Space Telescope (2008) with 4M micromirrors by Sandia NL Lucent’s Optical X-Connect

os, 9/16/99  GRATINGS - DIFFRACTIVE OPTICS Silicon Dioxide Silicon Nitride Silicon Substrate 25 to 100 µm Top electrode  1-D and 2-D spatial light modulators (Projection displays - Silicon Light Machines)  Displacement sensors (AFM arrays - C. Quate)  Sensor integration, free-space communication  Diffractive lenses and holograms (Fresnel zone plates - M. Wu, UCLA)

os, 9/16/99 System on a chip Laser-to-fiber coupling Micropositioners of mirrors and gratings High-resolution raster scanner

os, 9/16/99 Why Micromachined Adaptive Optics?  Parallel processing, large arrays, system integration, diffractive optics Standard IC materials and fabrication Integration of optics, mechanics, & electronics  Scaling of optics Alignment, Resolution, Optical quality, Mechanical actuation and stability Raster-scanning displays, Fiber-optic switches, Femto-second spectroscopy  Technology development actuation, mirror quality, integration  Conclusion

os, 9/16/99 Micromirror Structure Torsion Hinges Support Frame Mirror Surface Electrostatic Combdrive Substrate Hinge Frame Hinge Combdrive Linkage

os, 9/16/99 Fabrication PolySi Nitride Oxide SliderHinge Mirror V-groove for alignment

os, 9/16/99 Micromirror Reliability measurement # x Angle (degrees) “Off” position

os, 9/16/99 Video Display System Schematic Computer modulates a 10 mW 655 nm laser diode The emerging beam hits the fast scanning mirror The beam is then imaged to the slow scanning mirror 1f 2f The light is coupled into a single-mode fiber …and the image is projected onto a screen Demonstration system used two mirrors on separate chips

os, 9/16/99 Mirror Curvature Measurement Static deformation 1.2  m MUMPS Poly2  2-D Interferometry  Optical far-field measurements

os, 9/16/99 Mirror curvature due to actuation Mechanical deflection [deg] Optical beam radius (1/e 2 ) [  m] Mirror deformation due to actuation Degrees Wobble of actuated micromirror (motion on orthogonal axis)

os, 9/16/99 Video Display Scanned Images Resolution: 62 by 66 pixels, optical scanning angles 5.3 and 5.7 degrees a d e c f b g h

os, 9/16/99 Fiber Optic Crossbar Switch Optical DMUX Optical MUX  OXC  OXC Input Ports Output Ports  Architecture of WDM Switch The optical input signals are demultiplexed, and each wavelength is routed to an independent NxN spatial cross-connect Mirror Frame Comb drive Torsion bar 500  m SEM of the micromirrors used in the two-chip switch

os, 9/16/99 Switch characteristics Horizontal axis is in volts squared Optical Power Transmision [dB] Demonstration of Crossbar Switch Output Mirror Array Input Mirror Array 2X2 OXC design

os, 9/16/99 Scanning Mirror Optical Coherence Tomography Grating 760  m 5.3 cm Beam Splitter Delay line

os, 9/16/99 Polysilicon Grating Light Modulator 200 um 3um ribbons 6um grating period 150um electrode anchor ribbons

os, 9/16/99 GLM Operation Side view Beams up, reflection Beams down, diffraction Cross section

os, 9/16/99 Combdrive vs. parallel plate h dddd A cd =4Ndh End view

os, 9/16/99 Lessons for Adaptive Optics  Standard processes and materials High-resolution optics Mechanical stability & reliability => electrostatic actuation Large-stroke actuation => Combdrives  Optical quality SOI material  Integration wafer bonding => optimization of optics, mechanics and electronics  Novel functions - Diffractive optics Spectral filtering??

os, 9/16/99 Conclusion  Micromachining enables Adaptive Optics Miniaturization, arrays, integration, parallel processing, robustness, reliability Standard materials and processing  Low cost  Technology development Large-stroke electrostatic actuators High-quality optics Integration ÔWafer bonding ÔThrough-the-wafer interconnects  Novel functions Diffractive optics?? Spectral filtering??