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Similar to Optically Driven MEMS Mirror Array via Wafer Bonded GaAs/GaP PINs
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Optically Driven MEMS Mirror Array via Wafer Bonded GaAs/GaP PINs
- 4. Spring Plate Mirrors Dynamic correction using MEMS mirror
- 8. Working Principle I-V curve of the load resistor Equivalent circuit I-V characteristics of the PIN photodiode V Total = V PIN + V R V Mirror V Total V PIN V R
- 13. Interferometry Michelson interferometer setup Dark Light Difference Interference fringe patterns “ Patterned multipixel membrane mirror MEMS optically addressed spatial light modulator with megahertz response ” G.Griffith IEEE Photonics Technology Letters Vol.19 No.3 Feb 1, 2007 5-15 volts required for Mirror actuation
- 16. Photoresponse Testing Photo response test setup GaAs PIN (before bonding) Measurement probes 830nm LASER GaAs PIN sample Laser N P Probes
- 18. Wafer Fusion Schematic 3-D schematic of sandwiched wafers before fusion
- 19. Wafer Fusion 3-D schematic of fixture components Quartz tube Graphite fixtures Graphite shims
- 21. GaAs PINs on GaP Schematic of polished and patterned sample Schematic of polished and etched sample
- 22. GaAs PINs on GaP Wafer bonded interface GaAs GaP After polish & wet etch GaAs GaP
- 23. GaAs PINs on GaP Close up Cross section
- 24. GaAs PINs on GaP Top view
- 28. Final Device Spring plate and thin film resistor PIN with SU-8 pillars
- 29. Device Schematic
- 30. Final Testing On PIN diode On spring plate To Interferometer Work in progress!
Editor's Notes
- Mention name, photonics center, umass lowell advisor William Goodhue Speak the title
- Our group active in adaptive optics MEMS, device evolved New design, working priciple, optical Fabrication process, particularly interesting is the bonding Optical setup for I-V characteristics Finally, summarize
- Adaptive optics very important in fields like astronomy , LASER communication systems to remove atmospheric aberrations working principle : measures wave front distortion, and compensating for them using spatial phase modulators since these aberrations are constantly changing , dynamic correction using MEMS mirrors
- Adaptive optics very important in fields like astronomy , LASER communication systems to remove atmospheric aberrations working principle : measures wave front distortion, and compensating for them using spatial phase modulators since these aberrations are constantly changing , dynamic correction using MEMS mirrors
- Earlier work used mylar sheets, then moved to spring plates, electrical actuation All optical technique is much better for such devices as the arrays become smaller in dimensions and denser Earlier work with InGaAs detectors , 1550nm Now trying GaAs PINs
- Adaptive optics very important in fields like astronomy , LASER communication systems to remove atmospheric aberrations working principle : measures wave front distortion, and compensating for them using spatial phase modulators since these aberrations are constantly changing , dynamic correction using MEMS mirrors
- Incoming beam incident on the MEMS mirror Moving spring plate mirror made of SiN for correction Parallel plate capacitor Back illumination PIN diode Causes drop across thin film resistor made from TaN
- Idea is to get a voltage contrast across the spring plate Use a voltage source, or a fixed load resistor with current contrast The current contrast obtained from PIN detector (Light minus dark) Total voltage is sum of two, so easier to visualize on the same graph
- When no light is shining, its on point A When light shines, moves to point B So the following are desirable for optimum operation: High load resistance Acutation voltage as low as possible Lowest amount to dark current, and maximum current when light shines
- Simple interferometer setup Have a good understanding of the spring plate movement
- Simple interferometer setup Have a good understanding of the spring plate movement
- Mixed frequency results in lower stresses, which in turn means low actuation voltages InP etched with HCl Mechanical characterization done using comsol , and hysitron nanoindenter Optical characterization by monitoring fringes on Michelson interferometer
- Simple interferometer setup Have a good understanding of the spring plate movement
- We investigated various materials, but TaN is easier to fabricate and pattern High sheet resistance Explain figures
- Molecular beam epitaxy for controlled high quality growth Precise control of the growth rate and doping levels
- Molecular beam epitaxy for controlled high quality growth Precise control of the growth rate and doping levels
- Molecular beam epitaxy for controlled high quality growth Precise control of the growth rate and doping levels
- Molecular beam epitaxy for controlled high quality growth Precise control of the growth rate and doping levels
- Explain figure, and how we sandwich the samples face to face 2-D stress analysis used to optimize the fixture, for max stress on the samples, and least on the tubes
- Explain figure, and how we sandwich the samples face to face 2-D stress analysis used to optimize the fixture, for max stress on the samples, and least on the tubes
- Br-IBAE used for forming these pillars Though in final device we use wet etching to reach upto the P region
- Br-IBAE used for forming these pillars Though in final device we use wet etching to reach upto the P region
- Br-IBAE used for forming these pillars Though in final device we use wet etching to reach upto the P region
- Br-IBAE used for forming these pillars Though in final device we use wet etching to reach upto the P region
- Inverted microscope modified to test the samples Probes, and HeNe or 830nm
- Inverted microscope modified to test the samples Probes, and HeNe or 830nm
- After bonding the photo contrast drops to 20 micro amps, so requires higher load resistor to cause same drop across spring plate