Franklin & Marshall College Franklin & Marshall College

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  • Amy L. Lytle

    Assistant Professor of Physics
    717-358-4660
    Office: HACP206

    Education

    B.A., Physics, The College of Wooster, Wooster Ohio

    Ph.D., Physics, University of Colorado, Boulder Colorado 

    Research Interests

    Ultrafast and Nonlinear Optics

    My research background is in developing new, broadband laser sources in the near-infrared and soft x-ray regions of the electromagnetic spectrum. For my graduate work, I developed a new technique for boosting the efficiency of a nonlinear optical process called high-order harmonic generation (HHG). In HHG, high power, ultrafast laser pulses are upconverted in frequency from the near-IR (800 nm) to the soft x-ray region (~10-50 nm). The technique involves using counterpropagating light pulses to interfere with the conversion process. 

    The power of this counterpropagating technique is in its flexibility. It can be used in cases where other efficiency promoting techniques are impossible. Currently, I am exploring the application of this technique to second harmonic generation, a process similar to, but more widely used than, HHG. 


    Quantum Optics

    Since coming to F&M, Etienne Gagnon and I have become interested in an experimental test of Born's rule, which is a fundamental postulate of quantum mechanics. Introduced by Max Born in 1926, Born's rule mathematically defines the strange, probabilistic nature of quantum particles such as electrons of photons. It is extremely accurate in predicting outcomes to experimental measurements, but has neither been definitively derived nor experimentally verified.

    We are currently investigating an experiment using light diffraction as an experimental test of Born's rule. The experiment itself is straightforward, similar to ones done in introductory physics labs, but we have discovered that interpretation of its results is even more complicated than originally thought.


    Spectrally-Shaped Broadband Excitation of Upconversion

    Fluorescence occurs when a medium absorbs one frequency of light and emits another, thus converting the light to a different color. Most often, the emitted light has a lower frequency than the absorbed light. In upconversion, the medium absorbs more than one photon at a time, so that it may emit light of a higher frequency. This process has been used for the development of new laser sources, as well as the study of the dynamics of a process called excited state absorption.

    Nearly all studies of excited state absorption to date have used a single-frequency source to drive the absorption. We have recently developed a new technique using a broadband source of light, so that we can excite all available pathways at once. By spectrally-shaping the excitation light, we can gain information more directly about how the absorption occurs.


    Engineering Terahertz Sources

    I am also collaborating with Etienne Gagnon on his efforts to engineering more efficient and custom sources of light in the terahertz region of the spectrum (between infrared and microwaves). This type of light has been extensively studied recently due to its wide range of applications, including molecular dynamics, optoelectonics, and imaging for security purposes. Photonic tools for using this light, such as mirrors and lenses, are not easily available, however, so there is much work to be done in developing creative ways for manipulating terahertz.

    Most recently I collaborated with Etienne on developing a highly efficient and modular optical pulse-shaping technique for creating narrowband sources of Terahertz.

    Grants & Awards

    Cottrell College Science Award, Research Corporation for Science Advancement: 2012-2014

    National Science Foundation Graduate Research Fellowship: 2003-2006

    2008 New Focus/ Bookham Student Award

    Publications

     Selected recent publications:

    S. Adipa, A. L. Lytle, and E. Gagnon, "High efficiency, modular, optical pulse shaping technique for tunable terahertz generation from InAs," Appl. Phys. Lett. 102, 000000 (2013).

    P. Arpin, T. Popmintchev, N. Wagner, A. L. Lytle, O. Cohen, M. M. Murnane, and H. C. Kapteyn, “Enhanced high harmonic generation from multiply ionized argon above 500 eV through laser pulse self-compression,” Phys. Rev. Lett. 103, 143901 (2009). 

    (Invited) A. L. Lytle, X. Zhang, R. L. Sandberg, O. Cohen, M. M. Murnane, and H. C. Kapteyn, “Quasi-phase matching and characterization of high-order harmonic generation in hollow waveguides using counterpropagating light,” Opt. Express 16, 6544, (2008).

    A. L. Lytle, X. Zhang, P. Arpin, O. Cohen, H. C. Kapteyn, and M. M. Murnane, “Quasi- phase matching of high-order harmonic generation at high photon energies using counterpropagating pulses,” Opt. Lett. 33, 174 (2008).

    X. Zhang, A. L. Lytle, T. Popmintchev, X. Zhou, M. M. Murnane, H. C. Kapteyn, and O. Cohen, “Quasi-phase matching and quantum path control of high harmonic generation using coun- terpropagating light,” Nature Phys. 3, 270-275 (2007).

    A. L. Lytle, X. Zhang, J. Peatross, M. M. Murnane, H. C. Kapteyn, and O. Cohen, “Probe of high- order harmonic generation using counterpropagating light in a hollow waveguide,” Phys. Rev. Lett. 98, 123904 (2007).

    Presentations

    "Encouraging Class Preparation with Screencast Videos," at the Teaching, Learning, and Technology Discussions sponsored by ITS, 14 Nov 2012, with Etienne Gagnon

    "Understanding Nuclear Reactors and Radiation Doses," at a panel following the Fukushima reactor disaster, 23 March 2011, with Etienne Gagnon

    "Understanding and Manipulating Harmonic Generation," Invited seminar at Millersville University, 2 Feb 2011

    Student Collaborations

    Shawn Culbreth '11: Independent Study Spring 2011: Characterization of an Ultrafast Laser

    Allison Penfield '13: Hackman Summer Scholar 2011: Increasing the Efficiency of Second Harmonic Generation

    Rachel Myer '14: Independent Study Fall 2011: Data Analysis with LabVIEW

    Natalie Friedman '12: Independent Study Spring 2012: Data Analysis with LabVIEW

    Rachel Myer '14: Hackman Summer Scholar 2012: All-Optical Quasi-Phase Matching with Counterpropagating Light

    Lauren Tulchinsky '13: Hackman Summer Scholar 2012: Spectrally-Shaped Broadband Excitation of Upconversion in Rare-Earth Doped Nanocrystals

    Rumit Gambhir '15: Hackman Summer Scholar 2013: Experimental Error and Characterization of a Three-Slit Experiment for Testing Born's Rule

    Course Information

    Fall 2012: PHY 111 A Fundamental Physics I MWF 9:00 - 9:50 HAC 218
                       PHY 333 Electric&Magentic Fields MWF 10:00 - 10:50 HAC 220


    Spring 2012: PHY 111C Fundamental Physics Lab W 1:30 - 4:20 HAC 229
                            PHY 273 Optics  T, TR 12:45 - 2:05 HAC 220
                            PHY 273 Optics Lab, T, TR 12:15 - 3:35 HAC 220
     

    Fall 2011: Phy 111B Fundamental Physics Lab T 1:30 - 4:20 HAC 229
                       Phy 111C Fundamental Physics Lab W 1:30 - 4:20 HAC 229
                       Phy 111D Fundamental Physics Lab R 1:30 - 4:20 HAC 229

    Spring 2011: Phy 111A Fundamental Physics MWF 9:00 - 9:50 HAC218 

    Fall 2010: Phy 111C Fundamental Physics MWF 11:00 - 11:50  HAC218