IOS Seminar
An Ultrafast, Mid-wave Infrared Source for Driving High-order Harmonics Beyond the Water Window
Dr. Zachary “Alphonse” Marra
NRC Research Associate
Time: Friday, May 15th 2026 at 1:00PM
Location: Physics Research Building 4138
ABSTRACT: This talk presents the development of the world’s first cryogenically cooled Fe:ZnSe-based chirped pulse amplifier, a mid-wave infrared (MWIR) source designed for strong-field physics experimentation. By cryogenically cooling the Fe:ZnSe gain medium to extend its upper-state lifetime, the system makes use of free-running, diode-pumped Er:YAG pump lasers and a novel two-stage optical parametric amplifier seed. The resulting system produces 4.6 mJ, 247 fs pulses at a center wavelength of 4.07 µm, avoiding strong atmospheric CO2 absorption centered around 4.3 µm, to maintain high beam quality in ambient air. Furthermore, the demonstration of ninth-order harmonics and the generation of sub-40-fs pulses using gas-filled hollow-core fibers highlight the system's potential as a high-repetition-rate driver for isolated attosecond, keV-level X-ray pulses.
BIO: Dr. Zachary “Alphonse” Marra is an NRC Research Associate at the Air Force Research Laboratory (AFRL), Sensors Directorate, located at Wright-Patterson Air Force Base, where he leads the development of advanced mid-infrared laser systems. A recipient of the National Defense Science and Engineering Graduate (NDSEG) Fellowship, he earned his Ph.D. in Physics from the University of Central Florida, under the advisement of Prof. Zenghu Chang. During his doctoral research, Dr. Marra pioneered the first cryogenically cooled Fe:ZnSe chirped pulse amplifier, achieving record peak powers in the mid-infrared for strong-field science. Before joining AFRL, he served as a postdoctoral researcher at the University of Ottawa, focusing on terawatt-scale mid-infrared generation. He holds a B.A. in Physics and a Certificate in Entrepreneurship from the University of Wisconsin-Madison, where he contributed to the Atomic Qubit Array (AQuA) project for quantum computing.
- No Registration Needed - Refreshments will be provided - This event is open to the public -
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