Kenneth Poeppelmeier
Northwestern University, IL·Chemistry
Some crystals can change the color of laser light, for example turning red light into green. This effect, called nonlinear optics (NLO), is central to modern laser technology used in everything from eye surgery to particle accelerators.
- Fields
Chemistry
Materials Science
- Topics
noncentrosymmetric materials
nonlinear optics
second-harmonic generation
- Grants
- 1 known grant, through Mar 2027
What they work on
- Develop targeted hydrothermal, solvothermal and solid-state synthesis methods that control how anionic building units align in oxide and oxide-fluoride crystals, so that crystals form without inversion symmetry.
- Use machine learning on large sets of experimental data, together with chemical knowledge, to identify trends that guide the synthesis of new noncentrosymmetric materials.
- Grow large, high-quality crystals and determine their structures by single-crystal and powder X-ray diffraction, then measure second-harmonic generation and other properties to link structure to function.
More about the research
It happens only in noncentrosymmetric (NCS) solids, crystals whose atomic arrangement lacks a center of symmetry, so that the structure does not look the same when flipped through a central point. The same broken symmetry also gives rise to piezoelectricity (electricity from pressure), ferroelectricity and pyroelectricity (electricity from temperature change). This project uses chemistry to design and grow new NCS crystals and to link their atomic structures to their properties.
Why it matters
Emerging laser systems, including tunable lasers, need materials that convert laser light from one frequency to another efficiently. New noncentrosymmetric crystals and better design rules for making them could supply improved frequency-conversion materials for lasers. They may also yield new piezoelectric, ferroelectric and pyroelectric materials.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Allyson Fry-Petit
California State University-Fullerton, CA·Chemistry
Reproduce the reported synthesis of LK-99, the claimed room-temperature superconductor, and use in situ diffraction during the reaction to identify every phase that forms, including unstable intermediates.
Daniel Fredrickson
University of Wisconsin-Madison, WI·Chemistry
Develop computational tools to compare chemical pressure scaffolds, networks of overly compressed atom-to-atom contacts, across intermetallic crystal structures and connect them to material properties.
Daniel Bediako
University of California-Berkeley, CA·Chemistry·Early-career
Synthesize vanadium-intercalated TMD crystals, which have vanadium atoms inserted between layers, that are predicted to be altermagnets, using solid-state synthesis and crystal growth.
The school
Northwestern University: 71 labs on PI Pages, $1.3B a year on research, 536 research doctorates a year.
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