• Profile: Dr. Amy L. Lytle
Assistant Professor of Physics
Physics and Astronomy




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

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


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 Finalist



 Selected recent publications (*indicates F&M student co-author):

E. Gagnon, J. K. Krebs, and A. L. Lytle, "Selective control of excitation pathways of up-converted fluorescent states using a broadband laser and a spectral mask," submitted to Journal of the Optical Society of America B

E. Gagnon, C. D. Brown*, and A. L. Lytle, "Effects of detector size and position on a test of Born's rule using a three-slit experiment," Phys. Rev. A 90, 013832 (2014).

A. L. Lytle, E. Gagnon, L. Tulchinsky*, and J. K. Krebs, “Spectrally-shaped Broadband Study of Up-conversion in Y2O3 : Er3+,” J. Lumin. 152, 129 (2014).

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, 081106 (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).



(* indicates F&M student co-author)

"Testing the Foundations of Quantum Mechanics Using Light Interference," at the Post-Sabbatical Research Talk series sponsored by the Faculty Center, 7 Oct. 2014

R. Myer*, A. Penfield*, E. Gagnon, and A. L. Lytle, "Influencing the Conversion Efficiency of Second Harmonic Generation Using Counterpropagating Light," to be presented at Nonlinear Photonics (OSA Advanced Photonics Congress), Barcelona, Spain, July 2014. Paper JM5A.43

C. J. Brown*, E. Gagnon, and A. L. Lytle, “Effect of Detector Size and Position on a Test of Born’s Rule Using a Three-Slit Experiment,” OSA Frontiers in Optics/ DLS Laser Science, Orlando, FL, Oct 2013. Paper FTh1C.

"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

Spring 2015:        PHY 112 B, D   Fundamental Physics II  Lab 

Fall 2014:        PHY 112   Fundamental Physics II  w/ Lab
                          PHY 333   Electric & Magnetic Fields    

Fall 2013:        PHY 112   Fundamental Physics II w/ Lab
                          PHY 333   Electric & Magnetic Fields   

Fall 2012:        PHY 111 A   Fundamental Physics I   
                          PHY 333   Electric & Magnetic Fields  

Spring 2012:   PHY 111C   Fundamental Physics Lab    
                         PHY 273   Optics w/ Lab

Fall 2011:       PHY 111B, C, D   Fundamental Physics Lab  

Spring 2011:   PHY 111A   Fundamental Physics I 

Fall 2010:       PHY 111C   Fundamental Physics I