CPT John Zehnpfennig, CISSP, EIT
Instructor Contact: Office:
Room 1100 Thayer Hall Phone:
CPT Zehnpfennig is an Engineer and Functional Area 24 (Telecommunications Systems Engineer) officer who serves as an Instructor in the Electrical Engineering and Information Technology programs. He is also a Lead Researcher in the USMA/Army Photonics Research Center where he researches optical whispering gallery micro-resonators, particularly opto-mechanical interaction. His previous military assignments include enlisted Military Policeman, Executive Officer of an Army basic training company, Platoon Leader within one of the Army's three multi-role bridge building companies, and Commander of a Combat Engineer and Bridge Crewmember One Station Unit Training (OSUT) company. He is a 2000 Graduate of USMA Prep School, a 2004 Graduate (B.S., Electrical Engineering)of USMA, and a 2011 Graduate (M.S.E., Electrical Engineering, Optics and Photonics) of the University of Michigan, Ann Arbor. He is also a graduate of Military Police OSUT, Engineer Officer Basic Course, Signal Captains Career Course, and Telecommunication Systems Engineer Course. He has been deployed to Germany (1996-1999) and Iraq (O.I.F. 05-07, 2005-2006). He holds certification as an Intern Engineer (FEE/EIT) in the State of New York, (ISC)2 Certified Information Systems Security Professional (CISSP), CompTIA Security+ Professional, and Cisco Certified Network Associate. His academic interests include optical micro- and nanoresonators, sensors, local oscillators, IT security, elliptic curve cryptography, and routing algorithms. He is a member of the IEEE and the Eta Kappa Nu Electrical Engineer and Computer Scientist Honor Society.
- M.S.E., University of Michigan, Ann Arbor, 2011
- B.S., United States Military Academy, 2004
- J. Zehnpfennig, D. Covell, M. Letarte, J.J. Raftery, Jr "Surface Optomechanics: Analytic Solution of Detection Limits of Surface Acoustic Waves in Various Fluids" Frontiers in Optics 2012 (FiO). Rochester, NY. May 10, 2012. IN REVIEW; CONFERENCE IS 13-18 OCT 12. 2.(Cadet Co-authorship)
- J. Zehnpfennig, M. Letarte, R. W. Sadowski, J. J. Raftery, Jr. "Surface Optomechanics: Calculation of Love Surface Acoustic Waves on Microresonators" Conference on Lasers and Electro-Optics (CLEO) 2012. San Jose. May 6-11, 2012. 2. (Cadet Co-authorship)
- J. Zehnpfennig, G. Bahl, M. Tomes, T. Carmon "Surface Optomechanics: calculating surface acoustic wave generation on microsphere via photon-phonon interaction" XIV International Conference on Phonon Scattering and Condensed Matter. Ann Arbor, Michigan ACCEPTED FOR ORAL PRES 8-13 JULY 2012. March 1, 2012. 2.
- J. Zehnpfennig "Calculating and Observing Opto-Mechanically Induced Surface Acoustic Waves in Silica Whispering Gallery Microresonator" COMSOL Conference Boston 2011. Boston, MA. October 23-25, 2011. 4.
- J. Zehnpfennig, G. Bahl, M. Tomes, T. Carmon "Surface Optomechanics: Calculating Optically Excited Acoustical WhisperingGallery Modes in Microspheres" Frontiers in Optics/Laser Science (FIO/LS) 2011. San Jose, CA. October 16-20, 2011. 4.
- G. Bahl, J. Zehnpfennig, M. Tomes, and T. Carmon "Surface Optomechanics: Observation of Surface Acoustic Resonances in Whispering Gallery Resonators" Quantum Electronics and Laser Science Conference (CLEO-QELS) 2011. Baltimore, MD. May 26, 2011. 2.
- G. Bahl, J. Zehnpfennig, M. Tomes, and T. Carmon "Characterization of Surface Acoustic Wave Optomechanical Oscillators" IEEE International Frequency Control Symposium 2011. San Francisco, CA. May 15, 2011. 4.
- R. Perricone, S. Ravi, J. Zehnpfennig "Usability Study of Antivirus Software" University of Michigan CS588 Security Symposium 2011. University of Michigan, Ann Arbor, MI. April 12-14, 2011. 9.
- J. Zehnpfennig, G. Bahl. M. Tomes, and T. Carmon "Surface Optomechanics: Observation of Surface Acoustic Resonances" OSA Frontiers in Optics Conference 2010. Rochester, NY. POST DEADLINE SESSION. October 24-28, 2010. 1.
- J. Zehnpfennig, M. Tomes, and T. Carmon "Surface Optomechanics: Mechanical Whispering-Gallery Modes in Microspheres" IEEE Optical MEMS and Nanophotonics Conference . Sapparo, Japan. August 9-12, 2010. 2.
Journal and Printed Work
- John Zehnpfennig "Calculating and Observing Opto-Mechanically Induced Surface Acoustic Waves in Silica Whispering Gallery Microresonator" Proceedings CD of COMSOL Boston 2011. Moderator: Vladimir Leonov, available at www.comsol.com (13 Oct 2011) 6.
- G. Bahl, J. Zehnpfennig, M. Tomes, and T. Carmon "Stimulated optomechanical excitation of surface acoustic waves in a microdevice" Nature Communications. Vol. 2, Article 403, DOI: 10.1038/ncomms1412 (26 Jul 2011) 6.
- J. Zehnpfennig, G. Bahl, M. Tomes, and T. Carmon "Surface optomechanics calculating optically excited acoustical whispering gallery modes in microspheres" Optics Express. Vol. 19, Issue 15, pp. 14240-14248, doi:10.1364/OE.19.014240 (11 Jul 2011) 9.
- J. Zehnpfennig "Surface Optomechanics: Forward and Backward Scattered Surface Acoustic Waves in Silica Microsphere" Masters Thesis. University of Michigan, Ann Arbor (28 Apr 2011) 63.
- My primary area of research interest with the Photonics Research Center is the study of opto-acousitic whispering gallery resonators. I predict and observe how a silica (pure glass) micro-resonator vibrates when filled with light. This opto-mechanical interaction is caused by the "force of light" slamming into the atoms in the silica resonator. I have predicted and observed many different types of vibration waves within a wide range of frequencies.
You may be wondering "what is a whispering gallery?" This is one of the rare instances where a scientific term self-defines exactly what it means. A whispering gallery is a room, chamber, or 'gallery' where one can whisper a word and hear it amplified (sound louder), as well as hear the whispers of others in the 'gallery' at a level of loudness similar to a regular speaking voice. This occurs because the shape and material of the 'gallery' is such that the sound of the whisper 'goes around and around' the gallery without losing energy. Each time it goes around, it gains in strength. This effect was first described by Lord Rayleigh in his 1910 paper "The Problem of the Whispering-Gallery." A great whispering gallery at West Point is in Thayer Hall: the circular chamber near the 4th-floor north exit stairs leading to the Library.
We are able to make so-called "whispering gallery resonators" for light. The same effect happens: we put light (by this I mean laser light) in, and it whips around the resonator hundreds of millions of times. If we keep putting light in, then we end up with several hundred million 'pieces' of light (photons) whipping around together. By the coherent and wave natures of laser light, we are able to get these individual 'pieces' to add together to make a very strong 'light wave.' This light wave has enough energy to cause the molecules of the resonator to start shaking, thereby causing an ultra-acoustic wave (really high frequency sound wave) to begin to circulate in the resonator. Likewise, this acoustic wave 'parts' sum to make a strong wave that we can detect with simple lab equipment. We can then use these acoustic waves to sense changes in the environment (chemical, pressure, temp, etc) as well as build highly accurate clocks.
I continue this research at West Point, and welcome any Cadet who shares similar interests. Although I am an Electrical Engineering Instructor, the research work is open to Cadets who are willing and able to carry out the work, regardless of academic major or field of study. I have several potential Cadet research projects listed below. Conducting research and getting published is a great way to get into grad school and/or earn scholarships/fellowships. If you interested in researching with me, contact me and we'll work out a plan.
My goal is to publish at least one journal article per semester and submit novel work to several conferences each semester. Any Cadet co-Author will be invited to attend the conference and present the work to experts in the field. Common locations for these conferences include San Diego, Honolulu, Baltimore, San Jose, and Rochester, NY. Other conference opportunities around the world will also be considered.
Potential Cadet Projects
- Simulate Changes in Environment
Theory Work in COMSOL and MatLab
Using models I have developed in COMSOL (a CAD-like physics simulator), make changes to the material surrounding the resonator to quantify the effects of such changes. Observe and calculate the surface acoustic waveforms, and determine the resultant waveforms in the environment's media.
- Simulate Presence of Pollutant
Theory Work in COMSOL and MatLab
Using models I have developed in COMSOL (a CAD-like physics simulator), place nano- to micrometer scale pollutants on the surface of the resonator. Determine the effect to surface acoustic waveform type, frequency, and its interaction with the environment.
- Locate and Describe Love Surface Acoustic Waves
Theory Work in COMSOL and MatLab
Using models I have developed in COMSOL (a CAD-like physics simulator), seek out Love waves. Characterize the Love waves' frequency as azimuthal mode number varies.
- Observe Effect of Changing Environment
Using my research station in the Photonics Research Center, generate surface acoustic waves in a microresonator. While maintaining the resonance, change the surrounding media from air to other compounds. Observe effects in frequency. Develop mathematical model to describe effect of changing environment
- Observe Effect of Pollutant
Using my research station in the Photonics Research Center, generate surface acoustic waves in a microresonator. Then place nano- to micrometer scale pollutant(s) on the surface of the resonator. Determine the effect to surface acoustic waveform type and frequency. Determine tolerance of detection (eg. "how much/many pollutant(s) must be on the resonator before we can noticeably detect them?")
- Directly Observe Surface Acoustic Wave
Using my research station in the Photonics Research Center, generate surface acoustic waves in a microresonator. Using some form of 'microphone' directly measure the resonant frequency of the surface acoustic wave. Determine wave family based upon my previous simulated results as well as those performed by Cadets working on the theory portion of this research. Detect and explain any differences between the dirctly measured and simulated results.