1. Anirban Sarkar and Dooyoung Hah, “Electrophoretic deposition of carbon nanotubes on silicon substrates,” submitted to Journal of Electronic Materials.
   
   
2. Martin Feldman, Dooyoung Hah, Khalil Hanifa, and Zhongjie Zhang, “Capacitive soil moisture meter with a dynamic cone penetrometer (DCP),” Geotechnical Testing Jounal, accepted for publication.
   
   
3. Dooyoung Hah, John Bordelon, and Dan Zhang, “Mechanically tunable optical filters with a microring resonator,” Applied Optics, Vol. 50, Issue 22, pp. 4320-4327, Aug. 2011. (link)
   
   
4. Dooyoung Hah and Dan Zhang, “Analysis of resonant optical gyroscopes with two input/output waveguides,” Optics Express, Vol. 18, Issue 17, pp. 18200-18205, Aug. 2010. (link)
   
   
5. Jui-Che Tsai, Tien-Liang Hsieh, Chun-Da Liao, Sheng-Jie Chiou, Dooyoung Hah, and Ming C. Wu, “Experimental characterization of two-axis MEMS scanners with hidden radial vertical combdrive actuators and cross-bar spring structures,” Journal of Micromechanics and Microengineering, Vol. 19, No. 4, 045002, Mar. 2009. (link)
   
   
6. Seunghoon Park and Dooyoung Hah, “Pre-shaped buckled-beam actuators: theory and experiments,” Sensors and Actuators A: Physical, Vol. 148, Issue 1, pp. 186-192, Nov. 2008. (link)
   
   
7. Jui-Che Tsai, Sheng-Jie Chiou, Tien-Liang Hsieh, Chia-Wei Sun, Dooyoung Hah, and Ming C. Wu, “Two-axis MEMS scanners with radial vertical combdrive actuators—design, theoretical analysis, and fabrication,” Journal of Optics A: Pure and Applied Optics, Vol. 10, 44006, Apr. 2008. (link)
   
   
8. Jui-Che Tsai, Sophia Huang, Dooyoung Hah, and Ming C. Wu, “1xN2 Wavelength-Selective Switch with Two Cross-Scanning One-Axis Analog Micormirror Arrays in a 4-f Optical System,” IEEE Journal of Lightwave Technology, Vol. 24, No. 2, pp. 897-903, Feb. 2006. (link)
   
   
9. Ming-Chang M. Lee, Dooyoung Hah, Erwin K. Lau, Hiroshi Toshiyoshi, and Ming Wu, “MEMS-Actuated Photonic Crystal Switches,” IEEE Photonics Technology Letters, Vol. 18, No. 2, pp. 358-360, Jan. 2006. (link)
   
   
10. Wibool Piyawattanametha, Pamela R. Patterson, Dooyoung Hah, Hiroshi Toshiyoshi, and Ming C. Wu, “High Performance Surface- and Bulk- Micromachined Two Dimensional Angular Vertical Comb Actuators Scanner,” IEEE/ASME Journal of Microelectromechanical Systems, Vol. 14, No. 6, pp. 1329-1338, Dec. 2005. (link)
    
    
11. Dooyoung Hah, Chang-Auck Choi, Chang-Kyu Kim, and Chi-Hoon Jun, “A Self-Aligned Vertical Comb-Drive Actuator on an SOI Wafer for a 2-D Scanning Micromirror,” Journal of Micromechanics and Microengineering, Vol. 14, No. 8, pp. 1148-1156, Aug. 2004. (link)
    
    
12. Hung Nguyen, Dooyoung Hah, Pamela R. Patterson, Ru-Min Chao, Wibool Piyawattanametha, Erwin Lau, and Ming C. Wu, “Angular Vertical Comb Driven Tunable Capacitor with High Tuning Capabilities,” IEEE/ASME Journal of Microelectromechanical Systems, Vol. 13, No. 3, pp. 406-413, Jun. 2004. (link)
    
    
13. Dooyoung Hah, Pamela R. Patterson, Hung Nguyen, Hiroshi Toshiyoshi, and Ming C. Wu, “Theory and Experiments of Angular Vertical Comb-Drive Actuators for Scanning Micromirrors,” IEEE Journal of Selected Topics in Quantum Electronics on Optical Microsystems, Vol. 10, No. 3, pp. 505-513, May/Jun. 2004. (link)
    
    
14. Dooyoung Hah, Sophia Huang, Jui-Che Tsai, Hiroshi Toshiyoshi, and Ming C. Wu, “Low Voltage, Large Scan Angle MEMS Analog Micromirror Arrays with Hidden Vertical Comb-Drive Actuators,” IEEE/ASME Journal of Microelectromechanical Systems, Vol. 13, No. 2, pp. 279-289, Apr. 2004. (link)
    
    
15. Jui-Che Tsai, Sophia Huang, Dooyoung Hah, Hiroshi Toshiyoshi, and Ming C. Wu, “Open-Loop Operation of MEMS-Based 1xN Wavelength-Selective Switch with Long-Term Stability and Repeatability,” IEEE Photonics Technology Letters, Vol. 16, No. 4, pp. 1041-1043, Apr. 2004. (link)
    
    
16. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “A Low Voltage Actuated Microelectromechanical Switch for RF Application,” Japanese Journal of Applied Physics, Vol. 40, No. 4B, pp. 2721-2724, Apr. 2001. (link)
    
    
17. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “A Low Voltage Actuated Micromachined Microwave Switch Using Torsion Springs and Leverage,” IEEE Trans. Microwave Theory and Technology, Vol. 48, No. 12, pp. 2540-2545, Dec. 2000. (link)
    
    
18. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “An Optomechanical Pressure Sensor Using Multimode Interference Couplers with Polymer Waveguides on a Thin p+-Si Membrane,” Sensors and Actuators A: Physical, Vol. 79, Issue 3, pp.204-210, Feb, 2000. (link)
    
    
19. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “An Optomechanical Pressure Sensor Using Multimode Interference Couplers,” Japanese Journal of Applied Physics, Vol. 38, No. 4B, pp.2664-2668, Apr. 1999. (link)
    
    

  Peer-Reviewed Conference Proceedings

1. T.-L. Hsieh, Y.-T. Chang, S.-J. Chiou, J.-C. Tsai, D. Hah, and M. C. Wu, “Performance improvement of a two-axis radial-vertical-combdrive scanner by using a symmetric spring design,” International Conference on Optical MEMS and Nanophotonics, Freiburg, Germany, Aug. 11-14, 2008. (link)
   
   
2. S.-J. Chiou, T.-L. Hsieh, J.-C. Tsai, C.-W. Sun, D. Hah, and M. Wu, "A Two-Axis MEMS Scanner Driven by Radial Vertical Combdrive Actuators," International Conference on Optical MEMS and Nanophotonics, Hualien, Taiwan, R.O.C., Aug. 12-16, 2007. (link)
   
   
3. Seunghoon Park, Dooyoung Hah, "A Laterally-Driven Bistable RF MEMS Switch," The 7th Louisiana Materials and Emerging Technologies Conference, Baton Rouge, LA, USA, Oct. 23-24, 2006.
   
   
4. Chao-Hsi Chi, Chenlu Hou, Chi-Hung Lee, Dooyoung Hah, and Ming C. Wu, "Silicon-Based On-Chip Micromirrors for DWDM Wavelength-Selective Crossconnects," International Conference on Optical MEMS and Their Applications, Big Sky, MT, USA, Aug. 21-24, 2006, pp. 130-131. (link)
   
   
5. Chao-Hsi Chi, Jui-Che Tsai, Dooyoung Hah, Sagi Mathai, Ming-Chang M. Lee, and Ming C. Wu, “Silicon-Based Monolithic 4×4 Wavelength-Selective Cross Connect with On-Chip Micromirrors,” OFC/NFOEC 2006, Anaheim, CA, USA, Mar. 5-10, 2006. Paper OTuF1. (link)
   
   
6. Chao-Hsi Chi, Jui-Che Tsai, Dooyoung Hah, Ki-Hun Jeong, and Ming C. Wu, “Solid-Immersion Micromirror with Enhanced Angular Deflection for Silicon Based Planar Lightwave Circuits,” International Conference on Optical MEMS and Their Applications, Oulu, Finland, Aug. 1-4, 2005, pp. 131-132. (link)
   
   
7. Chao-Hsi Chi, Jui-Che Tsai, Ming-Chang M. Lee, Dooyoung Hah, and Ming C. Wu, “Integrated 1x4 Wavelength-Selective Switch with On-Chip MEMS Micromirrors,” CLEO/QELS 2005, Baltimore, MD, USA, May 22-27, 2005, pp. 1732-1734. (link)
   
   
8. Jui-Che Tsai, Li Fan, Chao-Hsi Chi, Dooyoung Hah, and Ming C. Wu, “A Large Port-Count 1x32 Wavelength-Selective Switch Using a LargeScan-Angle, High Fill-Factor, Two-Axis Analog Micromirror Array,” 30th European Conference on Optical Communication, Stockholm, Sweden, Sep. 5-9, 2004.
   
   
9. Jui-Che Tsai, Li Fan, Dooyoung Hah, and Ming C. Wu, “A High Fill-Factor, Large Scan-Angle, Two-Axis Analog Micromirror Array Driven by Leverage Mechanism,” International Conference on Optical MEMS and Their Applications, Takamatsu, Japan, Aug. 22-26, 2004.
   
   
10. Dooyoung Hah, Chang-Auck Choi, Chi-Hoon Jun, and Youn Tae Kim, “A Self-Aligned Vertical Comb-Drive Actuator using Surface Micromachining for Scanning Micromirrors,” International Conference on Optical MEMS and Their Applications, Waikoloa, HI, USA, Aug. 18-21, 2003, pp. 151-152. (link)
    
    
11. Wibool Piyawattanametha, Pamela R. Patterson, Dooyoung Hah, Hiroshi Toshiyoshi, and Ming C. Wu, “A 2D Scanner by Surface and Bulk Micromachined Angular Vertical Comb Actuators,” International Conference on Optical MEMS and Their Applications, Waikoloa, HI, USA, Aug. 18-21, 2003, pp. 93-94. (link)
    
    
12. Jui-Che Tsai, Sophia Hung, Dooyoung Hah, and Ming C. Wu, “1xN2 Wavelength-Selective Switch with Telescope-Magnified 2D Input/Output Fiber Collimator Array,” International Conference on Optical MEMS and Their Applications, Waikoloa, HI, USA, Aug. 18-21, 2003, pp. 45-46. (link)
    
    
13. Jui-Che Tsai, Sophia Hung, Dooyoung Hah, and Ming C. Wu, “Wavelength-Selective 1xN2 Switches With Two-Dimensional Input/Output Fiber Arrays,” CLEO 2003, Baltimore, Maryland, USA, Jun. 1-6, 2003. (link)
    
    
14. Jui-Che Tsai, Sophia Huang, Dooyoung Hah, and Ming C. Wu, “Analog Micromirror Arrays with Orthogonal Scanning Directions for Wavelength Selective 1xN2 Switches,” Transducers ’03, Boston, USA, Jun. 8-12, 2003. (link)
    
    
15. Wibool Piyawattanametha, Pamela R. Patterson, Dooyoung Hah, Hiroshi Toshiyoshi, and Ming C. Wu, “A Surface and Bulk Micromachined Angular Vertical Combdrive for Scanning Micromirrors,” OFC 2003, Atlanta, GA, USA, Mar. 23-28, 2003, paper TuN1. (link)
    
    
16. Sophia Huang, Jui-Che Tsai, Dooyoung Hah, Hiroshi Toshiyoshi, and Ming C. Wu, “Open-Loop Operation of MEMS WDM Routers with Analog Micromirror Array,” International Conference on Optical MEMS and Their Applications, Lugano, Switzerland, Aug. 23-26, 2002, pp. 179-180. (link)
    
    
17. Dooyoung Hah, Sophia Huang, Hung Nguyen, Hsin Chang, Jui-Che Tsai, Hiroshi Toshiyoshi, and Ming C. Wu, “Low Voltage MEMS Micromirror Arrays with Hidden Vertical Comb-Drive Actuators,” Hilton Head 2002 Solid-State Sensor & Actuator Workshop, Hilton Head Island, SC, June 3-6, 2002, pp.11-14.
    
    
18. Hung Nguyen, Dooyoung Hah, Pam Patterson, Rumin Chao, Wibool Piyawattanametha, and Ming C. Wu, “A Novel Tunable MEMS Capacitor Based on Angled Vertical Comb Drive Actuators,” Hilton Head 2002 Solid-State Sensor & Actuator Workshop, Hilton Head Island, SC, June 3-6, 2002, pp. 277-280.
    
    
19. Dooyoung Hah, Hiroshi Toshiyoshi, and Ming C. Wu, “Design of Electrostatic Actuators for MOEMS Applications,” Symposium on Design, Test, Integration and Packaging for MEMS/MOEMS, Cannes, France, May 6-8, 2002, pp. 200-207.
    
    
20. Dooyoung Hah, Sophia Huang, Hung Nguyen, Hsin Chang, Hiroshi Toshiyoshi, and Ming C. Wu, “A Low Voltage, Large Scan Angle MEMS Micromirror Array with Hidden Vertical Comb-Drive Actuators for WDM Routers,” OFC 2002, Anaheim, CA, USA, Mar. 17-22, 2002, Paper TuO3, pp. 92-93. (link)
    
    
21. Ming-Chang M. Lee, Dooyoung Hah, Erwin K. Lau, Hiroshi Toshiyoshi, and Ming C. Wu, “Nano-Electro-Mechanical Photonic Crystal Switches,” OFC 2002, Anaheim, CA, USA, Mar. 17-22, 2002, Paper TuO5, pp. 94-95. (link)
    
    
22. Ming C. Wu, Dooyoung Hah, Pamela R. Patterson, and Hiroshi Toshiyoshi, “Microelectromechanical Scanning Devices for Optical Networking Applications,” ISSCC 2002, San Francisco, CA, USA, Feb. 4-6, 2002, Paper 21.6. (link)
    
    
23. Pamela R. Patterson, Dooyoung Hah, Hung Nguyen, Hiroshi Toshiyoshi, Ru-min Chao, and Ming C. Wu, “A Scanning Micromirror with Angular Comb Drive Actuation,” 15th IEEE Micro Electro Mechanical Systems Conference (MEMS), Las Vegas, NV, USA, Jan. 20-24, 2002, Paper WP10, pp. 544-547. (link)
    
    
24. Pamela R. Patterson, G.-D. J. Su, Dooyoung Hah, and Ming C. Wu, “Integration of a Honeycomb Micromirror with a Surface Micromachined 2D Scanner for Improved Performance,” AVS 48th International Symposium, San Francisco, CA, USA, Oct. 29-Nov. 2, 2001.
    
    
25. Pamela R. Patterson, Dooyoung Hah, Hsin Chang, Hiroshi Toshiyoshi, and Ming C. Wu, “An Angular Vertical Comb Drive Actuator for Scanning Micromirrors,” International Conference on Optical MEMS and Their Applications, Okinawa, Japan, Sep. 25-28, 2001, pp. 25-26.
    
    
26. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “Low Voltage Actuated RF MEMS Switches Using Push-Pull Operation,” International Conference on Solid State Devices and Materials (SSDM), Sendai, Japan, Aug. 2000, pp. 392-393.
    
    
27. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “A Low Voltage Actuated Micromachined Microwave Switch Using Torsion Springs and Leverage,” IEEE International Microwave Symposium (IMS), Boston, MA, USA, June 11-16, 2000, pp. 157-160. (link)
    
    
28. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “Surface Micromachined Microwave Switch With Push-Pull Configuration,” The 2nd Korean MEMS Conference, Taejon, Korea, 2000.
    
    
29. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “Optomechanical Pressure Sensors Using Multi-Mode Interference Couplers on Thin p+-Si Membranes,” The 6th Korean Conference on Semiconductor, Seoul, Korea, 1999.
    
    
30. Dooyoung Hah, Euisik Yoon, and Songcheol Hong, “An Optomechanical Pressure Sensors Using Multi-Mode Interference Couplers,” International Conference on Solid State Devices and Materials (SSDM), Hiroshima, Japan, Sep. 1998, pp. 388-389
    
    
31. Dooyoung Hah, Young-Se Kwon, Songcheol Hong, “Optical Coupler Sensor with Movable Waveguide,” The 3rd Korean Conference on Semiconductor, Jeongju, Korea, 1996.

  Presentations (Including Invited)

1. Pamela R. Patterson, Dooyoung Hah, Makoto Fujino, Wibool Piyawattanametha, and Ming C. Wu, “Scanning Micromirrors: an Overview,” Proc. SPIE, Optomechatronic Micro/Nano Components, Devices, and Systems, Vol. 5604, pp. 196-07, Oct. 2004 (invited).
   
   
2. Dooyoung Hah, Chang-Auck Choi, Chi-Hoon Jun, Youn Tae Kim, Pamera R. Patterson, Hiroshi Toshiyoshi, Ming C. Wu, "MOEM scanners for optical networks," Proc. the 9th KIEE MEMS symposium, Seoul, Korea, 2003 (invited).
   
   
3. Ming-Chang M. Lee, Dooyoung Hah, Erwin K. Lau, Hiroshi Toshiyoshi, and Ming C. Wu, “Nano-Electro-Mechanical Photonic Crystal Switches,” 6th International Symposium on Contemporary Photonics Technology (CPT 2003), Tokyo, Japan, Jan. 15-17, 2003, pp. 135-138 (invited).
   
   
4. Ming C. Wu, Jui-Che Tsai, Sophia Huang, and Dooyoung Hah, “MEMS WDM Routers Using Analog Micromirror Arrays,” IEEE LEOS Annual Meeting (LEOS 2002), Glasgow, UK, Nov. 11-14, 2002, pp. 582-583, paper WBB4 (invited). (link)
   
   
5. Ming C. Wu, Dooyoung Hah, Sophia Huang, and Jui-Che Tsai, “MEMS Photonic Devices and Their Applications,” 7th Optoelectronics and communications conference (OECC 2002), Yokohama, Japan, Jul. 8-12, 2002, pp. 38-39 (invited).
   
   
6. Pamela R. Patterson, Dooyoung Hah, Ming-C. M. Lee, Jui-Che Tsai, and Ming C. Wu, “Recent advances in optical MEMS devices and systems,” International Symposium on Optical Science and Technology, SPIE's 47th Annual Meeting, Seattle, WA, July 7 – 11, 2002 (invited).
   
   
7. Ming C. Wu, Pamela R. Patterson, Dooyoung Hah, Ming-C. M. Lee, Sophia Huang, and Jui-Che Tsai, “Advanced MEMS for Photonics,” 60th Annual Device Research Conference, Santa Barbara, CA, June 24-26, 2002 (invited). (link)
   
   
8. Pamela R. Patterson, Dooyoung Hah, Hiroshi Toshiyoshi, and Ming C. Wu, “MOEMS Electrostatic Scanning Micromirrors Design and Fabrication,” 201st Meeting of the Electrochemical Society – 1st International Symposium on Integrated Optoelectronics, Philadelphia, PA, May 12-17, 2002 (invited).
   
   

  Patents

1. Martin Feldman and Dooyoung Hah, “Forward-Looking, Optical Coherence Tomography Endoscope,” PCT/US2007/080765, Oct. 9, 2007 (applied).
   
   
2. Ming C. Wu, Hung D. Nguyen, Dooyoung Hah, and Pamela R. Patterson, “MEMS Tunable Capacitor Based on Angular Vertical Comb Drives,” US-7,085,122, Aug. 1, 2006 (granted).
   
   
3. Dooyoung Hah, Ho-Jun Ryu, Chang-Auck Choi, Chi-Hoon Jun, and Youn-Tae Kim, “Scanning Micromirror for Optical Communication Systems and Method of Manufacturing the Same,” US-6,822,776, Nov. 23, 2004 (granted), and Korea-0469062, Jan. 20, 2005 (granted).
   
   
4. Ho-Jun Ryu, Dooyoung Hah, Chi-Hoon Jun, and Youn-Tae Kim, “Micro-Optical Switch Using Electromagnetic Force,” US-6,791,731, Sep. 14, 2004 (granted), and Korea-0451409, Sep. 22, 2004 (granted).
   
   
5. Songcheol Hong, Dooyoung Hah, “Microwave Double-Pole Double-Throw Switch and Microwave Divide/Through Switch and Power Amplifier Using thereof,” US-6,667,670, Dec. 23, 2003 (granted), and Korea-0403972, Oct. 20, 2003 (granted).
   
   
6. Songcheol Hong, Euisik Yoon, and Dooyoung Hah, “Micromachined Microwave Switch With Push-Pull Configuration,” Korea-335046, Apr. 19, 2002 (granted).
   
   
7. Songcheol Hong and Dooyoung Hah, “Optical Coupler Sensor with Movable Waveguide,” US-5,787,212, Jul. 28, 1998 (granted), and Korea-180972, Dec. 4, 1998 (granted).
   
   
8. Songcheol Hong and Dooyoung Hah, “Optical coupler 2 X 2 optical switch and method for optical switching therewith,” US-5,796,886, Aug. 18, 1998 (granted), and Korea-153860, Jul, 7, 1998 (granted).